Sheldon: Look at this. Elon Musk has a theory that we're all just characters in some advanced civilization's video game.
Leonard: So some alien kid spent his money on the asthma-and-glasses upgrade for me?
Sheldon: Well, he doesn't say it's a good game.

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.

Bernadette: I had a plan. I kept leaving Dove bar wrappers around to explain any weight gain.
Amy: Where did you get empty Dove bar wrappers?
Bernadette: From all the Dove bars I ate! I'm pregnant! Try to keep up!

Bernadette: Do you know what? It's just a research project. The most important job in the world is gonna be raising this child. It's all I need to give my life meaning.
Penny: Oh, that's so beautiful.
Bernadette: You believe me? Oh, good. Eleven more chumps like you, I'll have the jury eating out of my hand.

Sheldon: I don't understand why I can't talk at this meeting.
Leonard: 'Cause when you talk, it enrages people.