Leonard: Do you realize I don't live with the woman I love because of you? No other reason. Just you.
Sheldon: Is that true?
Leonard: Yes, it's true. The last time I brought it up, you had an emotional breakdown, got on a train, and ran away.

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.

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: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Penny: Sheldon, we know this is a sensitive subject, and Leonard's not going to move out until you're ready.
Sheldon: What if you did it gradually?
Leonard: All right, how about we start with two nights a week I live with Penny?
Sheldon: How about one night and I let you whistle?
Leonard: Okay.
Sheldon: When I'm not home.

Bernadette: Are you okay?
Raj: No, I'm not okay. I feel like I'm going to jump out of my skin.
Bernadette: I told you not to wax down there. It's itchy when it grows back.

Penny: Do I really force you to do things you don't want to?
Amy: Yeah, but it's okay.
Penny: How is it okay?
Amy: I promised myself if I ever got friends I'd do whatever they said. Really, I'm lucky you found me before a cult did.