Sheldon: Well done. You know, you're proving to be an invaluable part of my entourage.
Leonard: Cool.

Sheldon: I remember the song! It's called "Darlin'" by the Beach Boys! Oh, thank goodness! I'm not crazy! I don't have to take a pigeon as my bride!
Leonard: There goes our shot at him living on the roof.

Howard: Don't feel bad. Some day someone will be throwing out your work, too.
Leonard: That someone was Sheldon and the day was yesterday.

Professor Proton: Can I ask you a question?
Leonard: Yeah, sure.
Professor Proton: Why do you put up with Sheldon?
Leonard: Oh, you know because we're friends.
Professor Proton: Why?
Leonard: Wow, you ask really hard questions. Look, I know he can be aggravating, but what you have to remember is he's not doing it on purpose, it's just how he is. But he's also loyal and trustworthy and we have fun together.
Professor Proton: You know you're describing a dog?
Leonard: He did bite me once. But in his defense, I came up behind him while he was eating.
Professor Proton: They hate that.
Leonard: Sheldon is the smartest person I have met. He's a little broken and he needs me. And I guess I need him too.
Professor Proton: Why is that?
Leonard: Boy, you will not let this go, will you?

Sheldon: Thank you, Dr. Fowler. I have a very long and somewhat self-centered speech here. But I'd like to set it aside.
Penny: Yeah!
Howard: Way to go!
Sheldon: Because this honor doesn't just belong to me. I wouldn't be up here if it weren't for some very important people in my life. Beginning with my mother, father, meemaw, brother and sister. And my other family, who I'm so happy to have here with us. Is that Buffy the Vampire Slayer? I was under a misapprehension that my accomplishments were mine alone. Nothing could be further from the truth. I have been encouraged, sustained, inspired and tolerated not only by my wife, but by the greatest group of friends anyone ever had. I'd like to ask them to stand. Dr. Rajesh Koothrappali. Dr. Bernadette Rostenkowski-Wolowitz. Astronaut Howard Wolowitz. And my two dearest friends in the world, Penny Hofstadter and Dr. Leonard Hofstadter. I was there the moment Leonard and Penny met. He said to me that their babies would be smart and beautiful. And now that they're expecting, I have no doubt that that will be the case.
Penny: Thanks, Sheldon. I-I haven't told my parents yet, but thanks.
Sheldon: Oh. I'm sorry. Don't tell anyone that last thing. That's a secret.
Howard, Bernadette, Raj, Penny, Leonard, I apologize if I haven't been the friend you deserve. But I want you to know in my way, I love you all. And I love you. Thank you.

Sheldon: Carbon. Hydrogen. Carbon. Carbon. And last but not least, carbon.
Leonard: This might be the glue talking, but that was a very pleasurable 139 and a half hours.
Sheldon: Agreed.

Bernadette: You realize it's been years since we've got away just the two of us.
Howard: I know. I can't wait. Fancy hotel room. The big bed.
Bernadette: Yeah. We're gonna sleep our asses off.