Raj: I wish we could do more stuff without Sheldon.
Leonard: I wish that all the time. Usually before I blow out birthday candles.

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.

Amy: Hi, Sheldon.
Sheldon: Hello.
Amy: Are you feeling any better?
Sheldon: Physically, yes, but I'm upset because everyone's mad at me for no good reason.
Amy: Why don't you tell me what happened, and in a gentle, loving way, I'll explain to you why you're wrong.

Sheldon: Good. Then I'll be leaving now.
Emily: Oh, it's okay, Sheldon. Come with us.
Sheldon: Oh, that's very kind of you. But I'm sure you'll all have a better time without me. Let's go, Stuart.
Stuart: But I want to stay.
Sheldon: Stuart, now!

Sheldon: Raj, you were being a good friend, and my illness was no excuse for my behavior. I hope that you can accept my apology.
Raj: Of course I do.
Sheldon: And, Emily, I'm sorry for saying dermatologists aren't real doctors. And I'm sure you're tired of hearing that.
Emily: Do you honestly think I hear that a lot?
Sheldon: Well, I would imagine when your job is popping zits and squirting Botox into old lady faces-
Raj: Okay! Okay, the point is that we accept your apology.
Emily: Uh, maybe you do. He just insulted me again.
Raj: Yeah, but he doesn't mean it.
Emily: Why are you defending him?
Sheldon: I believe I can answer that. Uh, like me, Raj is demonstrating empathy.
Now, why don't you accept my apology, receive your free T-shirt, uh-- I hope extra small is okay. For some reason Wolowitz took a medium.