Sheldon: I am a grown man. I am a professional scientist. And I currently occupy the moral high ground.
Mary: Go to your room.
Sheldon: But I occupy the moral high ground.
Mary: Go to your room.
Sheldon: But I'm a professional scientist.
Mary: Go to your room!
Sheldon: *Backs away to his room* I'm a grown man.

Sheldon: Who's Nowitzki?
Ramona: I'm Nowitzki.
Sheldon: Oh, so you want me to share credit with you?
Ramona: Uh huh.
Sheldon: Get out!

Sheldon: But evolution is not opinion, it's a fact. Mary Cooper: And that is your opinion. Sheldon: [to Leonard, Howard and Raj] I forgive you, let's go home.

Sheldon: Careful, Amy. The friend of the enemy's girlfriend is my enemy.
Amy: Really?
Sheldon: You're either with me or against me.
Amy: You wanna take the bus to work?
Sheldon: Maybe there's a third option.

Sheldon: Hello.
Penny: Hello.
Sheldon: Ok, enough with the friendly banter. I believe you know why I am here.
Penny: Oh, I always figured it was to study us, discover our weaknesses, and report back to your alien overlords.
Sheldon: Yes amusing. Extraordinary intelligence might well appear extraterrestrial to you, but let me be more specific. I believe you know why I am here in the laundry room.

Sheldon: I've learned that 1 in 700,000 people die from general anesthesia.
Leonard: But do you realize that means 699,999 people don't die?
Sheldon: I suppose that's true. You're such a glass half full kind of guy. I'm going to miss that.

Sheldon: Proxima Centauri's the nearest star. The celestial bodies that follow are:
Alpha Centauri A, Toli, Barnard's Star, Wolf 359, Laland 21185, Sirius A, Sirius B, BL Ceti, UV Ceti, Ross 154, Ross 248, Epsilon Eridani, Lac 9352, Ross 128, EZ Aquarii A, EZ Aquarii B, EZ Aquarii C, Procyon A.
Those are the stars that are nearest to me,
Tra la la and fiddle dee dee.

Sheldon: I read an article about Japanese scientists who inserted DNA from luminous jelly fish into other animals; and I thought "Hey! Fish night-lights".
Leonard: Fish night-lights.
Sheldon: It's a billion dollar idea, ssh!

Sheldon: Get back here, you stupid bird, so I can love you.

Sheldon: What are you doing here?
Leonard: I live here.
Sheldon: I have paperwork that says differently.

Sheldon: I must say, Amy, pretending to have intercourse with you has given me a great deal of satisfaction.

Sheldon: Let's see. What do I know about Amy? She loves medieval literature. Chaucer's her favorite. And her eyes sparkle when she watches old French movies. And I enjoy how harp music causes her fingers to dance as if she's playing along.
Bernadette: Wow, you really do love her.
Sheldon: I do. Now, let's find the kind of gift that makes her feel small and worthless.

Sheldon: I need to sleep here tonight.
Raj: Why?
Sheldon: Howard is a total ass, Bernadette is in Penny's bed, Amy bites and Penny may or may not have coitus with Leonard.
Raj: Okay, come in.

Sheldon: I do feel obligated to point out to you that she did not reject you, you did not ask her out.
Leonard: You're right. I didn't ask her out. I should ask her out.
Sheldon: No! No that was not my point. My point was don't buy a cat.
Leonard: No, but you're right, I should march over there and ask her out.
Sheldon: Oh, goody! We're getting a cat.

Sheldon: The mean Indian lady tried to make me eat lamb.