Raj: I don't like bugs, okay. They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

Howard: Sheldon, don't take this the wrong way, but, you're insane.
Leonard: That may well be, but the fact is it wouldn't kill us to meet some new people.
Sheldon: For the record, it could kill us to meet new people. They could be murderers or the carriers of unusual pathogens. And I'm not insane, my mother had me tested.

Amy: This is an easy one. You love this guy.
Sheldon: Me.
Amy: Come on. He's an under appreciated genius.
Sheldon: Still think it's me.
Amy: It's not you. Now think, there's a car named after him.
Sheldon: Of course there is. The Mini Cooper because it's me.
Amy: How about this? He's a poor man's Sheldon Cooper.
Sheldon: Oh, Tesla.

Sheldon: May I say something?
Leonard: Not right now, Sheldon.
Sheldon: But I think it may be comforting.
Leonard: Buddy-
Howard: No, it's okay. What?
Sheldon: When I lost my own father, I didn't have any friends to help me through it. You do.

Amy: I've seen and talked to you more in the two days we've been broken up than in the last two months we were together.
Sheldon: Well, if you want to see less of me, maybe we should go out again.

Sheldon: Then it's settled. Amy's birthday present will be my genitals.

Penny: Why are there tears?
Leonard: Everything's fine. We just started talking about living arrangements.
Amy: Are you crazy? You know he's a flight risk!
Sheldon: That's exactly what I told him.

Amy: Let's see. I have been on six dates with three different people. It was either for coffee or dinner. One I met at a bookstore and two I met online. I haven't slept with anyone. The aquarium is 40 minutes away. And there's a baggie of Cheerios for you in the glove compartment.
Sheldon: Uh, regular or honey nut?
Amy: I mixed them.
Sheldon: You mixed them. No wonder gentleman callers are pounding down your door.

Sheldon: I've got to find a way to stop this thing.
Leonard: Buddy, I don't think you can. Once it's out there, it's out there. This thing is like the science equivalent of a sex tape.
Sheldon: Frankly, I'd prefer a sex tape.
Leonard: You don't know what a sex tape is, do you?
Sheldon: No.

Leonard: Our babies will be smart and beautiful.
Sheldon: Not to mention imaginary.

Sheldon: I know the real reason you never made progress with that idea. You thought of it September 22nd, 2007. Two days later, Penny moved in and so much blood rushed to your genitals, your brain became a ghost town.

Sheldon: Hello.
Leonard: Hey, buddy, can we have some privacy?
Sheldon: Of course. Wouldn't want to intrude. (takes red bra out of his pocket and hands it to Penny) This is yours.
Penny: Okay, when I'm done with him, I'm gonna need more information.
Sheldon: Nothing odd. I just wanted to rub Amy's nose in it.

Sheldon: I would have been here sooner but the bus kept stopping for other people to get on it.