Raj: Come on dude, that's my sister you're talking about.
Howard: Hey, Leonard jiggling his junk at her through a webcam has got to be easier for you to deal with than him actually touching her with it.

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.

Amy: You are aware that your ritualistic knocking behavior is symptomatic of obsessive-compulsive disorder?
Sheldon: Is not. Is not. Is not.
Amy: Denial. Denial. Denial.

Leonard: Sheldon, you do this all the time! You fixate on some crazy idea then blow it way out of proportion.
Sheldon: Name one time I've ever done that.
Leonard: How about the time you put GPS trackers in your garbage because you thought North Korean spies were stealing your doodles? The chicken nuggets you thought were human nuggets. The mysterious cloud that was following you around town. Or the time you put my shirt on by accident and thought you were growing again.
Sheldon: I said name one. You need to work on your listening skills.

Penny: What's up, buttercup?