Sheldon: Tell Mom that I currently weigh 165 pounds and that I'm having regular bowel movements.

Sheldon: Explain to me an organizational system where a tray of flatware on a couch is valid. I'm just inferring that this is a couch, because the evidence suggests the coffee table's having a tiny garage sale.

Leonard: Come on, you need a four-person team. We're four people
Sheldon: By that reasoning we should also play bridge, hold up a huppah and enter the Olympic bobsled competition.

Penny: You'll never guess what just happened.
Leonard: Oh, I give up.
Sheldon: I don't guess. As a scientist, I reach conclusions based on observations and experimentation. Although it occurs to me, you may have been employing a rhetorical device rendering my response moot.

Penny: I'm so sorry. I really thought if you guys went instead of me, he wouldn't be such an ass.
Leonard: No, it was a valid hypothesis.
Sheldon: "Was a valid hypo-" . What is happening to you?

Sheldon: Can't we just go to Big Boy? They only have one burger: the Big Boy.
Penny: The Barbecue Burger is like the Big Boy.
Sheldon: Excuse me, in a world that already includes a Big Boy, why would I settle for something that's like a Big Boy?

Sheldon: I'm a superior genetic mutation, an improvement on the existing mediocre stock.
Missy: And what do you mean "mediocre stock"?!
Sheldon: That would be you.

Sheldon: I will form my own team and will destroy the molecular bonds that hold your matter together, and reduce the resulting particular chaos to tears.
Leonard: Thanks for the heads up.

Amy: Sheldon, you've never worked in a lab like this before. You have no experience in the field of biology.
Sheldon: I have plenty of experience in biology. I bought a Tamagotchi in 1998. And it's still alive. Let's do this.

Mrs. Davis: Roots?
Sheldon: The tragic history of slavery in America. Fun for the whole family.
Mrs. Davis:: Why would you think this is an appropriate gift?
Sheldon: Umm. Well, you are black, right?

Sheldon: Well now I know how it must have felt being mauled by that sex-crazed gorilla.

Sheldon: Oh stop it. I don't need to take this admiration from the likes of you people.

Penny: Aww, that's great. You're going to be an uncle. Uncle Sheldon.
Sheldon: No, I will be Uncle Dr. Cooper.

Amy: Look, your anxiety levels are right in the zone.
Sheldon: Really? Oh, that's fantastic. No wait, they're dropping. Why are they dropping?
Amy: Because you're happy they're elevated.
Sheldon: Oh, that is infuriating. Oh look, they're going back up again. Terrific. Oh no, they're going back down.

Amy: According to the codicil of the Relationship Agreement which you insisted upon, we're not allowed to pout or be moody on date night.
Sheldon: You know I just put that in because of uterus stuff.