Dr. Koothrappali: Hello, Leonard, if I may also say your name.

Penny: So, Dr. Koothrappali, long flight?
Dr. Koothrappali: Twenty hours.
Penny: Ooh, that's rough.
Dr. Koothrappali: Not at all. Did you know that when you fly Transcontinental without your wife, you don't pray for the plane to crash?

Dr. Koothrappali: Relax? Easy for you to say. Your mother isn't cleaning out your bank account. Forty years, the woman never cleaned a thing.

Bernadette: But I thought I'd be more excited.
Dr. Koothrappali: Oh, being excited isn't a guarantee of anything. Rajesh's mother was thrilled when she was pregnant with him. After he was born, she doted on his every move. And you know what happened? He broke her heart, moved halfway around the world, and dates only poor white women. So you never know.

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?