Professor Proton: Rule number one in a marriage: don't go to bed angry.
Sheldon: That makes sense.
Professor Proton: Rule number two in a marriage: if you don't recognize the shoes under your bed, they're not your shoes.
Sheldon: Because they're her shoes?
Professor Proton: (sighs) N-Never mind, just-just go with rule number one.
Sheldon: Thank you, Arthur.
Professor Proton: Uh, before you go, can I ask you a question?
Sheldon: Of course.
Professor Proton: Does this look lean to you? I ordered lean.

Sheldon: I know why. You've come to me because you're my Obi-Wan.
Arthur: I'm not familiar with that. Is that an Internet?

Professor Proton: Oh, great, this again.

Professor Proton: Why isn't it ever Angie Dickinson's bedroom?

Bernadette: You okay? You seem distracted.
Howard: I'm just thinking about Raj.
Bernadette: I'm thinking about Chris Hemsworth.

Raj: Recently, 12 new moons were discovered orbiting Jupiter, bringing the total up to 79.
As a middle child myself, I'd like to extend my sympathies to moons two through 78. Your grandpa will never learn your name. I'd like to thank you for joining me on this journey through the stars. If you enjoyed this lecture, please come back Thursday for the exact same one.

Raj: I came here for your support.
Leonard: Well, then, you just walked up three flights of stairs for nothing.
Penny: Wait, don't you mean four flights?
Leonard: No, it's actually three.
Penny: But we're on the fourth floor. I mean, you have the lobby, first floor, second, third, fourth.
Leonard: The lobby's the first floor, so lobby, second, third, fourth.
Penny: That does not seem right.