Sheldon: I am also a son of the Lone Star state. I'm Texas through and through. And we know how to settle scores down there. If you doubt me, just ask Mexico.

Sheldon: Look at me, look at me, I've got goosebumps.

Sheldon: (Trying to keep Leonard from reaching his room) Wait. Come back. Halt. Authorized personnel only.

Sheldon: Hummingbirds are the vampires of the flower world.

Howard: You should've seen the look on your face!
Sheldon: Oh, yes. The slightly widened eyes of mildly startled.

Sheldon: It took me a gallon of urine to get that water!

Sheldon: Yeah, I hate wedding receptions. I wish the bride and groom would take a cue from Bilbo Baggins. Slip on the ring, disappear and everyone goes home.

Sheldon: I want you to be happy, too. But not enough to do anything about it.

Leonard: I thought Amy was going to drive you home.
Sheldon: I thought so too, but she's acting very strangely. I was discussing it with a Sri Lankan fella on the bus. He hypothosized that a tiger may have recently run across her shadow. Although he may have just been trying to drum up business for his brother-in-law's witchdoctor practice.

Amy: Come on, he's a retired kids show host.
Sheldon: That's even worse. Using the sweet candy of science to trick children into loving him. ... Pervert.

Professor Proton: Sheldon, what are you doing here?
Sheldon: I'm sorry, did I wake you?
Professor Proton: Of course you woke me, it's seven thirty.

Sheldon: I would have been here sooner but for some reason your home isn't on this map of Hollywood stars.

Sheldon: Yes, I'd be a physicist with a Nobel Prize in chemistry. Everyone laugh at the circus freak.

Wil Wheaton: Well not everybody felt that way. A lot of people really hated the character and some of them hated me because of it. I would do interviews and people would be mean to me.
Sheldon: That just happened to me. Next time you're stuck for a tweet, feel free to say what a jerk Ira Flatow is.

Sheldon: When I decided I was going to be a physicist, I didn't take some other job in case it didn't work. Which wasn't easy, because there was a lot of pressure from Ms. Pearson to be chalk monitor that year.