Penny: Do you not want me to be friends with your mom?
Leonard: Well, let's be clear. I-I married you to hurt her. You're kind of ruining it.

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: What about this?
Raj: Uh, okay. Uh, pull off the skirt, slap a lightning bolt on the front, and you got baby Flash. Ooh, stick a long sleeve under it. Boom, Baby Sheldon!

Leonard: Come on. You can build things. You were an astronaut.
Howard: That's true. You know, as a kid, I used to make model rockets. That'd be pretty cool to do with a son.
Sheldon: Model rockets. Finally, something interesting! What is your preferred mode of recovery?
Amy: Sheldon, we're helping our friends.
Sheldon: And we got to model rockets, yeah? It was a tedious road, but well worth the effort.
Amy: So, have you thought of any names?
Sheldon: Amy, we finally got to model rockets. Why are you turning back?

Sheldon: You're a good teacher. Your son is going to be lucky to have you as a father.