Leonard: Ladies,
Emily: Are you being polite or scared?
Leonard: Yep.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Howard: I'm sorry I didn't take you to the airport. I just want you to know I'll never forgive myself for being so selfish. And I promise to keep you close for the rest of my life.
Bernadette: Oh, no, that thing's gonna end up in my bedroom.

Bernadette: You better find my husband's mother, 'cause one way or another we're walking out of this airport with a dead woman.

Penny: Do you want to stop? I know you have trouble with eye contact.
Sheldon: Well, you have a brown fleck in your right iris that looks like a Formula 1 race car, so I'm just concentrating on that. Plus it's easier around people I'm comfortable with.
Penny: Oh, sweetie, I'm comfortable around you, too.
Sheldon: Of course you are. I'm warm and soothing. I'm like a human bowl of tomato soup.