You mess with the bull, you get the horns. I'm about to show this guy just how horny I can be.

Leonard: Uh, another one says, "The concept shows some real out-of-the-box thinking".
Sheldon: Do you hear that, Mr. Out-Of-The?
Leonard: I do, indeed, Mr. Box-Thinking.

Leonard: You're sure it's good?
Sheldon: My name is right on there with yours. That is a surefire
mark of quality. That might as well say "Directed by Joss Whedon".
Leonard: Okay, partner, let's do it.

Leonard: You wrote a paper on my idea?
Sheldon: I wrote a paper on our idea.
Leonard: When did my idea become our idea?
Sheldon: When I mixed it with Sheldony goodness and cooked it in the Easy-Bake Oven of my mind.
Leonard: This is good. Our idea is really good.
Sheldon: Well, the light bulb in this oven is ridiculously bright.

Leonard: You're giving me a sticker?
Sheldon: Not just a sticker. That is a sticker of a kitty saying, "Me-wow!"
Leonard: I'm not a preschooler.
Sheldon: Fine, I'll take it back
Leonard: I earned this! Back off!

Penny: Sheldon, we are just people. we talk about the same things you guys talk about.
Sheldon: You talk about if werewolves can swim?

Sheldon: I don't want to tell you how to do your job, but when a mouse completes a maze it gets a food pellet.
Amy: It also gets its brain plucked out with tweezers.
Sheldon: And its last meal was a food pellet? You're a monster.

Sheldon: Nothing more fun than a paradigm shifting evening of science.
Penny: (to Leonard) And you thought it was soaping me up in the shower.

Sheldon: There were plenty of ways to pass the time before smartphones were invented.
Leonard: That's true.
Sheldon: I'll look them up... Oh, son of a biscuit!

Amy: Well, you got me something. Here.
Sheldon: Cookies?
Amy: They're your Meemaw's Christmas cookies. I called and got
the recipe.
Sheldon: They're perfect. It tastes like her hugs.
Amy: Merry Christmas, Sheldon.
Sheldon: I can't believe this. You're happy, I'm happy. Well, maybe a holiday that's all about giving isn't so...Get your hand out of that box!

If you pop him, I will vomit.

Raj

Santa: All right, let me see if I've got this straight. A picture of you on my lap is a way to punish your girlfriend for making you celebrate Christmas?
Sheldon: Correct.
Santa: Santa thinks dating you may be punishment enough.
Sheldon: There's an argument for that.

TBBT Quotes

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.

Leonard: Hi. I'm Leonard. You are beautiful. You pop, sparkle and buzz electric. I'm going to pick you up at eight, show you a night you will never forget.
Raj: Where are we going?