Sheldon: No, that's okay. I can fight my own battles. Isn't that right, Bawwy?
Barry Kripke: Is that a reference to my speech impediment? That's pretty hurtful. I can't control it.
Sheldon: You're right. That was uncalled for. I take it back.
Barry Kripke: Of course you do, because you're The Retractor!

Penny: (To Raj's dog) Bark once if you need me to call PETA.

Sheldon: What's that animal doing in our apartment?
Leonard: She's in her crate, she can't get out.
Sheldon: I have two words for you: Jurassic Park.

Sheldon: This day just keeps on getting worse and worse.
Penny: You know, if it makes you feel any better ...
Sheldon: It probably won't.
Penny: You're probably right.

Sheldon: Thank you. Ira, if I may, I'd like to aplogize for my behavior last week. Now, isn't there something you'd like to say to me?
Ira Flatow: No.

Raj: Sheldon, I think you might find the support you're looking for if you realize relationships are a give and take. She can only be there for you as much as you are for her.
Amy: Thank you, Rajesh.
Raj: And Amy, you need to be patient with Sheldon and stop pressuring him into accepting intimacy on your terms.
Amy: You should probably go.

Sheldon: To really understand the story here, we need to start at the very beginning. A small town in East Texas where a young genuis named -
Leonard: - Sheldon!
Sheldon: Yes, that's right, Sheldon Cooper. He was bitten by his neighbor's dog, leading to his first scientific break through: the Doggy Death Ray. Which sadly he couldn't build because Santa wouldn't bring him enriched uranium.

Ira Flatow: You know, I'd really like to hear from Dr. Hofstadter if it's all right with you.
Sheldon: What a surprise. Did you invite me back just so you could ignore me.
Ira Flatow: Actually, I didn't invite you. You came in, you took a seat, and I'm not comfortable with confrontation.

Penny: You know if we did a shot every time they said something embarassing, this would be one hell of a drinking game.
Amy: Little early for alcohol, isn't it?
Sheldon: (On the radio) You know, I don't just say smart things about science, I also yodel. *Yodelling*
Amy: I'll get the vodka.

Leonard: The math is all there. It's not real.
Penny: Yes, it is.
Sheldon: Look, it's scientifically impossible for a person to tip a cow. Even you with your stocky build and lumberjack shoulders.

Raj: Why would you push a cow over? They're sacred.
Penny: Oh, stop it. I've seen you eat like a million hamburgers.
Raj: Hey, an animal can be both sacred and delicious.

Penny: Look, I'm telling you I've done it. I clearly remember the cow standing up and then a cow on its side.
Leonard: Were you drunk?
Penny: I was sixteen and in Nebraska, what do you think?
Leonard: I think you're the one who fell over.
Penny: Well that would explain why the sky was also on its side.

Penny: Howard, cow tipping - real or not?
Howard: I'm going to say not. That's just based on me trying to roll my mom over when she's snoring.

Sheldon: I've been told that a bald refusal of an invitation is rude and one must instead offer up a polite excuse. So, I'd love to but unfortunately that sounds awful.

Leonard: It would actually be nice to not hear Sheldon complain about my cooking all day.
Sheldon: Excuse me. Every year you prepare a terrible meal and every year I criticize it. Do our traditions mean nothing to you?