Penny: What's up, buttercup?

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

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

Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

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.

Amy: Kiss me where I've never been kissed before?
Sheldon: You mean like Salt Lake City?