Leonard: Well, I am shocked, Sheldon, because I totally believed that the woman you reported for being stingy with the peas couldn't keep her hands off you.

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?

Bernadette: Hey, Denise. Is Stuart here?
Denise: Oh, no. Doctor's appointment.
Bernadette: Oh, is he okay?
Denise: Not since I've known him.

Sheldon: You know we're almost finished with our paper; we just need help tracking down the citations.
Leonard: That's busywork. Can't you just get a grad student to do it?
Amy: No, this paper is incredibly important to us, and we need someone we can trust.
Please, it would mean a lot.
Leonard: You know what? Sure. The three of us in the library looking up old papers, that actually could be kind of fun.
Sheldon: Oh, no, we won't be there.
Leonard: It just got more fun.

Sheldon: I suppose you're wondering why I put you through all this.
Leonard: You mean the last two minutes or the last 20 years?