Penny: I meant more like a little brother.
Sheldon: Oh. Well, I suppose I do think of you like a sister. And sometimes a mother.
Penny: It's getting creepy again.

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

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Howard: I'm not signing a prenup.
Penny: All right, Howard Wolowitz, listen up! You sign anything she puts in front of you, because you are the luckiest man alive. If you let her go, there is no way you can find anyone else. Speaking on behalf of all women, it is not going to happen, we had a meeting.

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

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.

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.