Amy: Well, I am a little hurt that you weren't gonna tell me my husband was having an affair. I thought we were friends.
Leonard: I didn't really believe him.
Amy: Why not? You don't think other women find him attractive?
Leonard: (laughing) No.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

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?