Penny: Once again, unbelievable.
Sheldon: Yeah, once again, I know.

Sheldon: You know, I am very disappointed that I won't be able to celebrate Howard's accomplishment tonight.
Amy: Me, too. But we'll see him tomorrow.
Sheldon: Yes, it's just that in all the years I've known him, he's never had the opportunity to receive my admiration. I was excited to see the look on his face when it finally happened.

Penny: You're unbelievable.
Sheldon: I know.

Sheldon: Yeah, you had a good run, fake Wolowitz. We'll remember you with nostalgic fondness. The way we do the dial-up modem, the VHS tape, or Leonard's gym membership.

Leonard: I don't have a problem with Stuart. Besides, he gives us a 20% discount at his comic book store.
Sheldon: Well, I don't sell my friendship that cheaply.
Stuart: I can go 30.
Sheldon: Welcome aboard, old chum.

Sheldon: If you're going to replace Wolowitz, I need to know a little bit more about you.
Stuart: All right.
Sheldon: Wolowitz went to MIT. What's your educational background?
Stuart: I went to art school.
Sheldon: Equally ridiculous. Let's go.

Sheldon: Penny, please don't hurt my friend.

Sheldon: Settle down there, fake Wolowitz. No one likes a kiss-up.

Leonard: I know what the anthropic principle is.
Sheldon: Of course. I just explained it to you. Now, where do you stand on it?
Leonard: Where do you stand on it?
Sheldon: Strongly pro.
Leonard: Then I believe that God created the world in six days and on the seventh he made you to annoy me.

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.

Sheldon: Gotta run. (Looks down at scissors) But not with scissors, that would be unsafe.

Sheldon: I assume we're talking about you now?
Leonard: Yeah.
Sheldon: So that's how this works, I complain and then you complain and no one offers any solutions?
Leonard: Pretty much.
Sheldon: Well no wonder the women are winning.

Sheldon: The need to find another human being to share one's life with has always puzzled me. Maybe because I'm so interesting all by myself. With that being said, may you find as much happiness with each other as I find on my own.

Leonard: You'll never guess what just happened.
Sheldon: You went out in the hallway, stumbled into an inter-dimensional portal, which brought you 5,000 years into the future, where you took advantage of the advanced technology to build a time machine, and now you're back, to bring us all with you to the year 7010, where we are transported to work at the think-a-torium by telepathically controlled flying dolphins?
Leonard: No.
Sheldon: Awww.
Leonard: Penny kissed me.
Sheldon: Who would ever guess that?

Sheldon: Hello.
Penny: Hello.
Sheldon: Ok, enough with the friendly banter. I believe you know why I am here.
Penny: Oh, I always figured it was to study us, discover our weaknesses, and report back to your alien overlords.
Sheldon: Yes amusing. Extraordinary intelligence might well appear extraterrestrial to you, but let me be more specific. I believe you know why I am here in the laundry room.