Leonard: Why don't we go get the food for the party?
Stuart: Thank you.
Raj: Smart. Looks like we're being helpful.
Leonard: When really we're just exiting an uncomfortable situation. *fist bumps with Raj*

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.

Sheldon: May I say something?
Leonard: Not right now, Sheldon.
Sheldon: But I think it may be comforting.
Leonard: Buddy-
Howard: No, it's okay. What?
Sheldon: When I lost my own father, I didn't have any friends to help me through it. You do.

Penny: At one point, they had me figure out how to get a banana out of a puzzle box.
Leonard: Wait, Sheldon gave me a banana in a box. He was testing me, too.
Penny: Unbelievable.
Leonard: And how could a chimp even solve that? That was impossible.
Penny: Really? You couldn't get it out?

Bernadette: She's just being nice.
Howard: Well, I'm her son, how come she doesn't send someone to check on me if I'm lonely.
Bernadette: Because you have a wife!
Howard: Yeah, well, sometimes you work late.