Penny: You're over-thinking this.
Leonard: No, I'm not.
Penny: Yes, you are. You always over-think things.
Leonard: Ah, now there you go. Always made it worse.

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.

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

Bernadette: Boy, I don't know if I could be friends with Howie if we broke up.
Howard: Why not?
Bernadette: I'm a very vengeful person.
Howard: Really?
Bernadette: With access to weaponized smallpox.

Sheldon: Does anybody have any wood? Oh, come on! I just want wood. Why are you making it so hard?

Sheldon: I know he (Spock) wouldn't care for an outburst of human emotion, but oh goodie, oh goodie, oh goodie!