Raj: The only thing missing from that insult was "yo momma."
Howard: I've got one. Hey, Leonard, your momma's research methodology is so flawed-
Leonard: Shut up, Howard.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a forklift?

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Leonard: Is this the stuff you want me to try on?
Penny: No this is the stuff I want you to throw out. Seriously, don't even give it to charity. You won't be helping anyone.

Sheldon: Just the latest copy of Applied Particle Physics Quarterly.
Penny: Oh, you know, that is so weird that yours came and mine didn't.

Leonard: You are not Isaac Newton.
Sheldon: No, no, that's true. Gravity would have been apparent to me without the apple.