Raj: Hey, you should totally get it. In fact, I'll buy it for you.
Stuart: Sold!
Emily: Raj, you don't have to do that.
Stuart: Too late! No returns!

Stuart: Oh, Sheldon, I'm afraid you couldn't be more wrong.
Sheldon: More wrong? Wrong is an absolute state and not subject to gradation.
Stuart: Of course it is. It's a little wrong to say a tomato is a vegetable, it's very wrong to say it's a suspension bridge.

Howard: Hang on, I know a place where you could you stay and earn some money at the same time.
Stuart: Great!
Howard: I just have to warn you: it will involve humiliation, degradation and verbal abuse.
Stuart: So, what's the catch?

Bernadette: Hey, Stuart.
Stuart: *startled* Hey.
Bernadette: Sorry, did I startle you?
Stuart: Yes, but at this point pretty much any customer does.

Leonard: What am I supposed to do?
Penny: Err, keep your mouth off other women.

Penny: Wait, what is wrong with you two? He was talking about television during their date night.
Sheldon: Oh, not just date night. Our 5th anniversary.
Penny: Okay, see, that's even dumber than you wondering if being bitten by a goat would give you the powers of a goat.
Sheldon: If that happens, don't make me wait ten years to watch you eat a tin can.

Sheldon: Amy's mad at me, and I'm not clear why.
Penny: Okay, were you talking before she got upset?
Sheldon: Yes.
Penny: That's probably it.