Raj: I'm sorry, guys. Sheldon was upset, Leonard and Penny were fighting. I just wanted to go someplace where I wasn't causing problems.
Howard: (sighs) I'll say it again. India.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a forklift?

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Amy: This isn't about me and Sheldon. This is about Rajesh moving in with Leonard and Penny.
Beverly Hofstadter: Interesting. They've found a need to take yet another roommate. Seems they're avoiding some harsh realities themselves.
Sheldon: I had no idea all our relationships were such a disaster. Boy, you're good.
Beverly Hofstadter: That is the word on the street, dear.

Sheldon: What if she's correct? Doesn't that say something troubling about us?
Amy: I don't know. I just think you're the kind of person who likes a contingency plan.
Sheldon: That is true. Did you know I figured out in which order I would eat all my friends in the event of an apocalypse?
Amy: You need to stop hanging out with your brain so much. It's not a good influence.

Penny: Well, it's like that science thing. For every action, you have a gigantic and annoying reaction.
Leonard: Just when I thought you couldn't get any hotter.