Leonard, Penny, Howard, and Bernadette go to dinner for Valentine's Day while Sheldon and Amy search for the perfect gift for each other. Stuart and Raj plan a party for individuals who are not in a relationship at the Comic book store.
At Penny's place, Leonard and Penny are having dinner and she tells him about her day and how she saved a man's life. Leonard asks if she gave someone the Heimlich maneuver and she replies that she had yelled out that a man was choking. The busboy gave the man the Heimlich maneuver. Leonard said that she was a hero and Penny told him that that was the point of the story. Leonard then asked her if she had Thursday night off since it was Valentine's Day. She said that she was off and they could do something. She finds that there's lots of pressure to make it special and it never works out that way. Leonard tells that it's going to be special because he is the Ninja of Romance and she won't see it coming. Penny replies that she had thought she had made him a lot cooler until he does something like that.
In the apartment building stairwell, Sheldon and Amy climb the stairs as Sheldon keeps talking about how their spicy food can be felt on the way out and that both ends must have some sense of taste. Amy agrees with him, but still wants to know what they are doing on Valentine's Day.
At the comic book store, Howard is on the phone with Bernadette looking anxious to get off, constantly saying "O.K." Raj then asks him if he is OK. Howard tells him that Bernadette is cranky after working seventeen-hour days -- and he's been spending a lot of time playing Assassin's Creed. Raj and Stuart decide to throw a Valentine's Day party at the comic book store for all those who don't have dates. Stuart likes the idea. Raj explains that they can celebrate the greatest love a man can have, himself.In Sheldon's office, Sheldon finds Alex and asks her to work on a research project he is having a problem with. Alex is excited to help him with his scientific work. Sheldon dismisses her remark and tells her that that is not going to happen. He wants her to find Amy a Valentine's Day gift. She tells him that she passed up a job at another lab to work with him. Sheldon then tells her that they'll have to find someone else to buy gifts for their girlfriends. He gives her $2000 in various crumbled bills and tells her he thinks Amy likes monkeys and the color grey. Sheldon talks to himself, repeating how Alex wanted to contribute to his work, ending with "kids say the darnedest things".
In his lab, Howard creates a micro-valentine present for his microbiologist wife. Over 12 hours, which really took time away from his video game playing, he used an atomic force microscope from the materials science lab to write his and Bernadette's initials in a heart 1/1000th the size of a grain of sand. Leonard adds that it's from a micro-husband. Howard then accidentally breaks his gift when he removes it from the microscope, so Leonard invites them to come to dinner with Penny and he.At Sheldon's place, Sheldon tells Alex that Amy will be showing up shortly expecting the perfect Valentine's gift and tells Alex to dazzle him. Alex checked out Amy's Facebook page and chose three potential gifts for Sheldon. The first was a harp music box that plays one of her favorite songs. Sheldon counters that she has a real harp that can play any song. Next Alex knows that Amy likes The Canterbury Tales and got her a map showing the characters' journeys. Sheldon tells her that she already has Google Maps on her phone. Alex replies that she doesn't know how to respond to that, a comment that Sheldon sometimes makes. Since Amy is a neuroscientist, she researched the subject and found a signed drawing of a brain cell made by Santiago Ramón y Cajal, the father of modern neuroscience. Sheldon likes the drawing so much that he keeps it and waves away Alex's protest that the gift was for Amy by declaring "I called dibs."
At dinner, Penny loves the restaurant. Bernadette and Howard show up fighting because Howard didn't wash her clothes and he had been playing Assassin's Creed, so she hid his Xbox. Howard tells her that he is not a child and that if she doesn't tell him where it is, he is going to tell his mother. Bernadette tells them that she had been working late every night and that all she asked him to do was to clean the apartment and do a load of laundry. Leonard tells them that they are trying to have a magical night. Then, Penny notices at another table a couple she despises (her old boyfriend and the girl that broke them up). First, she notices that the woman has lost a lot of weight and then she tells Leonard that their night is going to be way more special than the other couple's night. The guy immediately gets down on one knee and proposes. Leonard sees how upset Penny is and says that two can play this game. He gets down on one knee, but Penny tells him to get back up.
Raj and Stuart are getting ready for the party which Stuart is looking forward to because there is no place that he would rather be than his comic book store. Raj counters except on a date with anyone, which Stuart agrees with. Raj then says that they get along so well, that is a shame that he’s not a girl whom he could take home and has wild sex with. Stuart looks concerned after Raj's last comment.
Back at the restaurant, the other couple is getting along very well. Penny can't believe that he is marrying the woman he cheated on her with. Leonard thought it was nice that she was at one time the wrong girl and now she's the right girl. Penny snaps that now she is the wrong girl? Why doesn't he also go over there to be with Gretchen? Penny claims that this Valentine's Day sucks and Leonard adds that it's because of her. They continue to argue as Howard and Bernadette feel that their conflict was minor compared to Leonard and Penny's and they make-up. Howard tells Bernie that they'll leave early and he'll go home and do her laundry. Bernadette tells him that he'll find the Xbox in the washing machine.
Amy shows up at Sheldon's door telling him "Happy Valentine's Day". Sheldon merely agrees with her. Amy says that she had planned a traditional night of romance while Sheldon planned on faking enjoyment and had worked on a new smile to go with it. After much contemplation, Amy felt that she was being selfish, canceled their dinner reservations and came up with a new plan. No romance or gifts. They are going to stay at home, order a pizza, and watch one of his beloved Star Trek things. Since that was what he loved, so that is what they are going to do. Sheldon found that to be the most amazing gift anyone ever gave to him. Amy tells Sheldon to take back whatever he got her since she knows how much pressure gift giving puts on him. Sheldon then shows Amy that she is down as his emergency contact at the university, which brings Amy to tears that he trusts her that much. She hugs him tightly as Sheldon tells her to stop ruining Valentine's Day and order his pizza.
Penny and Leonard come up the stairs with her saying good night and Leonard replying "Yep" as she goes into her apartment. Leonard turns around and walks in without knocking. First, he tells her that he tried to give her a romantic night and she went out of her way to destroy it. Penny agrees and says that she is a total bitch. Leonard asks why she acted that way. She explains to Leonard that everything is going so well with them and that she is really happy, which confuses Leonard. She finally admits that she has some commitment issues. Since things are going well, she explained, you're going to keep asking me to marry you and someday she'll say yes and they'll be married forever and the whole thing freaks her out. Leonard agrees that he proposes to her a lot. Then, he says that he will never propose to her again. Penny is taken aback, afraid that he is breaking up with her. He assures her that he isn't-- just that when she is ready; she can be the one to propose to him. He does, however, say that if that time comes, she has to get down on one knee, give him flowers, and sweep him off his feet, but no Jumbotron proposals. Penny agrees. She then tells Leonard she has to ask him something important. Leonard looks startled. She looks into his eyes and says, "Leonard Hofstadter... Will you be my Valentine?" Leonard gets up and walks off, saying, "Sorry, maybe next year." Penny gasps, and Leonard turns back, grinning, saying he was just kidding. Even after a dramatic night, they are each other's Valentines.
Back at the comic book store, Dale is talking to Raj and Stuart thanking them for the party. Dale says that usually on Valentine's Day he is sad and alone, but tonight he is just sad. They wonder why everyone has to be so sad on this night. Raj makes a nice speech that they aren't mutants just because they are alone. They should not define their self-worth as to whether they are in a relationship. They are a community as long as they have each other. Then a girl named Lucy approaches Raj telling him that his speech was cool. Raj thanks her and asks her to go out for coffee. As he leaves, he tells the guests, "Later, losers!"
Finally, in her lab, Amy finds that she is getting a lot of emergency calls about Sheldon since she is his point-of-contact, which does not thrill her, but she still goes to help him.
- Guest starring:
- Teleplay: Steven Molaro, Jim Reynolds & Tara Hernandez
- Story: Chuck Lorre, Bill Prady & Steve Holland
- The TV Critic: "To my surprise the writers seem to have finally moved Penny and Leonard toward a more committed state this season...It was about as sweet a scene as I can remember them sharing when he realizes that she is happy with where they are...Amy and Sheldon also took another step forward but at their own ultra-slow pace. The fact that he was willing to buy her a gift says something and the emergency contact was a very nice idea. While it is a sign of intimacy and commitment it leads to her becoming his mom in the final scene as his hypochondria kicks in. Her tearful gratitude was sweet though and his attitude to the gifts Alex had selected was fun."
- Oliver Sava of The A.V. Club gave the episode a B+.
- Jesse Schedeen of IGN gave the episode a "good" rating: 7.2/10.
- Dhruv Rao of The DR Club gave the episode a C.
- IMDb user reviews
- Title Reference: The title comes from the Valentine's Day theme and the various ways the TBBT couples demonstrate their affection for each other.
- Chuck Lorre's vanity card.
- This episode was watched by 22.24 million people with a rating of 7.5 (adults 18-49).
- Total viewers including DVR users 22.24 million.
- This episode aired in Canada on May 9, 2013 with 3.877 million viewers and a weekly ranking of #1.
- In the United Kingdom, this episode aired on with 2.357 million total viewers.
- Episode transcript 
- First appearance of Lucy and the final appearance of Alex.
- Penny's former girlfriend named Gretchen that gets the marriage proposal and upsets Penny is played by Kaley's younger sister Briana Cuoco.
- Leonard makes his second marriage proposal to Penny; she tells him to sit down before he can reveal her last name, assuming he was going to say it. When he finally proposes he still only calls her Penny in "The Gorilla Dissolution" (S7E23).
- Alex Jensen asks Sheldon, "You do realize I gave up an opportunity at Fermilab to come work for " She does not engage in work commensurate with her standing as a graduate research assistant (GRA).
- The chubby redheaded nerd with Rosacea (played by Jesse Heiman) at the comic book store party is the same nerd who kisses a supermodel (Bar Refaeli) in the GoDaddy Super Bowl XLVII commercial. He has previously appeared as a member of Wil Wheaton's entourage in "The 21-Second Excitation" (S4E8) and "The Stag Convergence" (S5E22)
- Second episode whose plot is set around Valentine's Day. The previous was "The Large Hadron Collision" (S3E15) where Leonard wanted to take Penny to Switzerland.
- According to Mayim in the season 6 featurette, an early draft of the script had Amy and Sheldon kissing during their Valentine's date; however they did kiss until the next Valentine's Day episode in the next season (S7E15 - The Locomotive Manipulation).
- Sheldon's desire to keep a brain cell drawing which was brought as a Valentine's gift for Amy is unsurprising since Sheldon has shown knowledge of neuroscience before Amy's introduction.
- When Amy rushes out of her lab to attend to Sheldon's medical emergency, she still snatches up her medical gloves, which she clearly didn't need to bring.
- As of this episode, Stuart is demoted back to recurring character, but is re-promoted to main character in "The Locomotion Interruption" (S8E1).
- Raj: Can I have your attention please? We’re all here tonight because we have no one to be with, but this doesn't make us mutants. The only mutants here are in these comic books. Let us stop defining our self-worth by whether or not we’re in a relationship. You know what I see when I look around? I see a room full of great people. So let’s give ourselves a break. We are a community and as long as we have each other we’re never truly alone.
- Leonard: You know what. That was pretty crappy of you. All I wanted to do was give you a great night and it’s like you went out of your way to destroy it.
- Penny: Yep. I know. I’m a total bitch.
- Leonard: I’m not saying that.
- Penny: Well, I am.
- Leonard: Well. Fine you win. You’re a bitch. Why couldn't we just have a nice time?
- Penny: I don’t know. Maybe because things are going so well between us lately and I’m been really happy.
- Leonard: O.K. You’re going to have to make a lot more sense than that.
- Penny: Obviously I have some commitment issues.
- Leonard: We’re in the obvious. Go on.
- Penny: As long as things keep going great between us, you’ll keep asking me to marry you and eventually I’m going to end saying yes then we’re going to be married forever and the whole think just freaks me out.
- Leonard: O.K. I know I propose a lot so how about this. I promise I will never ask you to marry me again.
- Penny: What? What do you mean? Are you breaking up with me?
- Leonard: No. No, no, no, no, no. But if someday you decide to you want to get married, you have to propose to me.
- Penny: Really?
- Leonard: Yes. All on you. But I got to tell you when the time comes I want the whole nine yards. I want you down on one knee, flowers; I want to be swept off my feet.
- Penny: You got it.
- Leonard: And I’m cool with surprises, but nothing on the Jumbotron. I don’t to cry on a big screen like that.
- Penny: O.K. You know what, this might be the wine talking, but I have a very important question to ask you.
- Leonard: You do?
- Penny: Leonard Hofstadter.
- Leonard: Yes.
- Penny: Would you be my valentine?
- Leonard: Sorry, maybe next year. I’m just kidding. Romance ninja! Let’s have sex! Wo-ah! [Penny laughs and they kiss.]
- Sheldon: Ah, Alex, excellent. I have a research problem that I believe you can help with.
- Alex: Oh, Dr. Cooper, thank you. I've been waiting for an opportunity to contribute to your scientific work.
- Sheldon: Oh, no, no. That’s not going to happen, no. What I need you to do is find a Valentine’s gift for my girlfriend.
- Alex: You realize I passed up an opportunity to work at Fermilab to take this job with you.
- Sheldon: Well, I guess those chaps will have to have someone else buy their girlfriends presents. Now, here is, let’s see, this is, this is about two thousand dollars, um, I think she likes monkeys and the color grey. Contribute to my work. Ah, kids say the darndest things.
- Amy: And I appreciate your effort, but upon contemplation, I decided I was being selfish. So, I canceled our dinner reservations and came up with an even better way to celebrate Valentine’s Day.
- Sheldon: What is that?
- Amy: By doing none of it. No dinner, no romance, no gifts. We stay here, order a pizza and watch one of your beloved Star War Trek things.
- Sheldon: Really?
- Amy: Well, that’s what you’d love, isn't it?
- Sheldon: More than anything.
- Amy: Well, then, that’s what we’re going to do.
- Sheldon: Well, I don’t know what to say. This is the most thoughtful gift that anyone’s ever given me. And that’s including an amazing gift that I gave myself earlier today.
- Amy: I’m your girlfriend. That’s my job. And I know gift-giving puts a lot of pressure on you, so whatever you got me, you can return.
- Sheldon: No. No, after everything you didn't do for me tonight, I want you to have it.
- Amy: What’s this?
- Sheldon: Read it.
- Amy: Sheldon Cooper, Cal Tech University employee information?
- Sheldon: At the bottom.
- Amy: In case of emergency, please contact… Amy Farrah Fowler. And there’s my phone number. This is the most beautiful gift you could've ever given me.
- Sheldon: Well, I thought, if I have a stroke or a kidney stone, who would I want to share that with?
- Amy: And you picked me.
- Sheldon: It’s like you said, you’re my girlfriend.
- Amy: Oh, Sheldon.
- Sheldon: Yeah. Okay. Stop ruining Valentine’s Day and order my pizza.
- Sheldon: So, in conclusion, I believe the painful sensation felt after passing a meal of spicy chilies is proof that the rectum does possess the sense of taste.
- Amy: I concur, but you changed the subject. What are we doing for Valentine’s Day?
- Sheldon: Oh, you caught that did you?
- Penny: This place is really beautiful.
- Leonard: Waugh, romance ninja.
- (Penny giggles and sips her wine just as the really aggressive Howard and Bernadette arrive at the table that Leonard and Penny are sitting on).
- Penny: Hey.
- Howard: Sorry we’re late.
- Penny: No problem. We just sat down.
- Leonard: (he's asking Bernadette) Mmm, would you like some wine?
- Bernadette: (she is already very cross) Yeah, fill her up.
- (Leonard pours the wine into Bernadette's glass for a second and then he stops himself while Bernadette says one last thing to Leonard crossly)
- Bernadette: (she is still very cross) I’ll tell you when to stop.
- (Leonard pours the wine again while Penny asks a question to Howard)
- Penny: Is everything okay?
- Howard: (sarcastically) Terrific. Couldn’t be better.
- Bernadette: (she is so completely cross with Howard) Oh, bite me.
- Howard: (he speaks aggressively) Look, we can still have a nice night. Just tell me where it is.
- Bernadette: (she is even more crosser) Maybe if you did what you said you were going to do, I’d tell you.
- Leonard: Uh, where what is?
- Howard: (he is now really angry) She hid my Xbox like I’m a child. (Leonard nods sarcastically just as he scolds loudly at Bernadette) Yeah, and my mom got me that for my birthday, so if you don’t give it back, I’m telling.
- (Penny looks disgusted at Howard and Bernadette's arguement)
- Bernadette: (she yells at the trio angrily) I’ve been working late every night. All I asked was that he clean the apartment and do one load of laundry. But did he do it? No.
- (Scene of Penny and Leonard reacting at Bernadette's angry voice referring to Howard)
- Bernadette: (she's yelling offscreen) He just kept on playing that stupid game.
- (Scene of Bernadette so gigantically cross with Howard)
- Bernadette: You like pushing buttons so much, try pushing them on the washing machine.
- (Penny and Leonard react for a second each)
- Howard: (firmly) I said I’m sorry.
- Bernadette: (she is still gigantically cross) Sorry doesn’t clean my underpants, buddy.
- Howard: (he argues sarcastically to her) I told you, turn them inside out.
- (The still completely angry Bernadette is several times more crosser)
- Bernadette: (she argues angrily to him) And I told you to bite me.
- Leonard: Trying to have a magical night here, guys.
- (Scene of Howard shaking his head whilst Bernadette carries on with getting a billion times angry, Penny has now finished another sip of wine and sees something from afar)
- Penny: (grumpily) Oh, son of a bitch.
- Leonard: What?
- Penny: Nothing. Nothing.
- Leonard: No, tell me.
- Penny: It’s just this guy I used to date.
- Leonard: Oh.
- Penny: Until he cheated on me with my friend Gretchen, who’s here with him now.
- Leonard: You’re kidding.
- Penny: And it looks like she lost a lot of weight, damn it.
- Leonard: I know it’s not ideal, but don’t let them ruin our night.
- Penny: No, you’re totally right. She could be skinny ’cause she’s dying.
- Leonard: That’s the spirit.
- Penny: You know what, screw them. Our night is going to be way more special than theirs.
- Leonard: Yeah.
- Bernadette: (she is very worried) Uh-oh.
- Penny: What? (Penny’s ex is proposing to Gretchen) Oh, you got to be kidding me.
- Gretchen: Oh, my God, yes. Of course I’ll marry you.
- Leonard: Two can play this game. Penny…
- Penny: Get up.
- Leonard: All right.
- Penny: Oh, I can’t believe he’s going to marry the girl he cheated on me with.
- Leonard: Isn’t it kind of nice? I mean, he was with the wrong person, and now he found the right person.
- Penny: What, so I’m the wrong person? Maybe you want to be with Gretchen, too.
- Bernadette: (still very cross) They do look happy.
- Howard: Yeah, maybe tonight. But a year from now, he’ll be crawling under the sink looking for his Xbox. Well, he will.
- Leonard: You know what? Why don’t we just forget about them and enjoy our Valentine’s Day?
- Penny: Yes, absolutely. Now they’re doing that phony link-arm-drink thingy. I totally taught him that.
- Leonard: I thought we were letting it go.
- Penny: We were; it’s just, it’s not fair, okay? They’re bad people. It’s not supposed to end happy for them, it’s supposed to end happy for me.
- Leonard: Um, it did end happy for you. You’re here with me.
- Penny: Yeah, yeah, I know.
- Leonard: Okay, this is getting a little hard to not take personally.
- Penny: Oh, come on, don’t make this about you.
- Leonard: Oh, I’m not. It’s about you.
- Penny: Yeah, well, whatever, okay? I told you, Valentine’s Day sucks.
- Leonard: This one does, and you’re the reason why.
- Penny: What?
- Bernadette: You know, compared to them, I’m feeling pretty good about us.
- Howard: Me, too. How about we blow off dessert, go home early, I’ll do that laundry.
- Bernadette: (proud) Thank you.
- Howard: I love you.
- Bernadette: Love you, too.
- Howard: So where’d you hide it?
- Bernadette: Where you’d never look.
- Howard: Damn it, it’s in the washing machine.
- Taping Report by MJistheBOMB
- ↑ The Big Bang Theory - The Tangible Affection Proof (TV Episode 2013) - IMDb
- ↑ The TV Critic's review The TV Critic's Review
- ↑ The Big Bang Theory: “The Tangible Affection Proof” - TV Club - The A.V. Club
- ↑ The Big Bang Theory: "The Tangible Affection Proof" Review - IGN
- ↑ The Tangible Affection Proof/S6E16 - The DR Club
- ↑ Live+7 DVR Ratings: 'Modern Family' Leads Adults 18–49 Ratings & Total Viewership Gains; 'Glee' Earns Biggest Percentage Increase in Week 21 - Zap2it
- ↑ Top Programs – Total Canada (English) February 11, 2013 – February 17, 2013 - BBM Canada
- ↑ BARB via Wikipedia
- ↑ GoDaddy Breakout Nerd's First Post-Super Bowl Appearance: 'Big Bang Theory', Sophie Schillaci, 4 February 2013, The Hollywood Reporter