Raj: You know what, I think it's a little weird that you remember me saying all these things. Maybe the truth is you're jealous of all my relationships.
Howard: Oh. Maybe I am. Who wouldn't want to the girl - or possibly dog - to hear the words "You're so lucky. You have the shiniest hair."
Leonard: That is a tough one. I know he brushes both of them.

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.

Howard: I invented a game. Want to play?
Leonard: Sure.
Howard: It's called Emily or Cinnamon. I give you actual quotes I've heard Raj say, and you guess if he was talking to his girlfriend or his dog.

Leonard: At least listen to it through headphones. I'm trying to sleep, good night.
Sheldon: Boy. Taylor was right. Haters gonna hate, hate, hate, hate, hate.

Amy: Look, your anxiety levels are right in the zone.
Sheldon: Really? Oh, that's fantastic. No wait, they're dropping. Why are they dropping?
Amy: Because you're happy they're elevated.
Sheldon: Oh, that is infuriating. Oh look, they're going back up again. Terrific. Oh no, they're going back down.