Penny: I'll pay you back as soon as I can.
Sheldon: Of course you will. It's impossible to pay me back sooner than you can. Assuming you subscribe to a linear understanding of time and causality.

Leonard: See, Howard's just as good a dungeon master as I am.
Sheldon: As good? You just got pantsed in the schoolyard, four eyes.

Sheldon: I've never knocked on my own door before. That was a wild ride.

Sheldon: Please let me know when you and your girlfriend are done hogging the bandwidth for your self-abuse. I'm trying to stream a movie on Netflix in here.

Leonard: You know, some people might say that it's great that we're trying to make things work long distance. They'd say things like, love is stronger than the miles between you.
Sheldon: When I rise to power, those people will be sterilized.

Sheldon: I miss the days when your romantic partners could be returned to the video store.

Raj: They get girlfriends and they just abandon us?
Sheldon: It is great, isn't it? We have a wonderful evening ahead of us.

Raj: Come on, Sheldon, the world is filled with people doing things outside. Let's go outside. Outside is good.
Sheldon: If outside is so good, why has mankind spent thousands of years trying to perfect inside?

Sheldon: I would like a root beer float.
Raj: Sheldon, they don't have ice cream.
Sheldon: They don't? Well, apparently these people and I differ greatly on the definition of party.

Raj: He'll have a Shirley Temple.
Sheldon: And don't be chintzy with the Shirley.

Sheldon: I've decided that I'm going to have Mr. Lee sign my copy of this month's Batman.
Howard: That's crazy. Stan Lee had nothing to do with Batman.
Sheldon: Yes, which is why no one else will ask him to sign one, and I will be the possessor of a unique, albeit confusing, artefact, which will set me apart from the hoi polloi of comic book fandom

Howard: Sheldon, why do you have all these unopened paychecks in your desk?
Sheldon: Because most of the things I'm planning to buy haven't been invented yet.
Howard: But there must be thousands of dollars here. Why don't you put it in the bank?
Sheldon: I don't trust banks. I believe that when the robots rise up, ATMs will lead the charge.

Amy: I need someone to accompany me to the wedding of Dr. Moranelli and Dr. Gustafson this Friday. They're kind of the Brad and Angelina of the primatology department.
Leonard: Wouldn't you rather bring Sheldon?
Amy: I would, but the last wedding we went to was a disaster. He behaved like a child the entire time.
Sheldon: Not my fault. You said there'd be other scientists there my age.

Sheldon: Try to put yourself in my place. Imagine you're the sole human being living on a planet populated with nothing but dogs. And then it turns out there's another human being.
Howard: Hang on, are you saying the rest of us are dogs?
Sheldon: Okay. I can see you're going to take this the wrong way. Let me try again. Imagine you're the sole human being on a planet populated with nothing but chimps.
Howard: Get out of my lab.
Sheldon: Oh, now they're much smarter than dogs. Have you seen them on those bicycles?
Howard: Get out.
Sheldon: How about dolphins?

Sheldon: That's a lot of belt buckles.
Howard: Funny thing is, I have only one belt. Anyway, I'll get you started. Oh, by the way, the little marks that look like water spots, I tend to stand too close to the urinal, so what you're seeing there is splash back.
Sheldon: You make sissy on your belt buckles? Mee-Maw's forks never had that.