Mary: Shelly, you don't really need a tie.
Sheldon: I have to find my tie. I have to find my tie.
Mary: Be right back.
Sheldon: Professor Proton wears a bow-tie!

Mary: Let's say grace.
Sheldon: Hang on, safety first. [puts mittens on]
George Jr.: When are you gonna get over that?
Sheldon: I would think recent events would make you value protection.
Mary: Enough.

Ms. MacElroy: Now, can anyone tell me why Melville shifts the narrative voice from Ishmael to Ahab? [Ms. MacElroy waits for somebody else to raise their hand] Sheldon.
Sheldon: I have a tummyache. I'd like to see the nurse.
Derek: A "tummyache"?
Sheldon: Yes, Derek, I have a tummy and it aches. Ergo, tummyache.
Derek: Ergo?
Sheldon: It's Latin, Derek.
Ms. MacElroy: Go to the nurse.
Sheldon: And to answer your question, the shifting point of view grants the reader a broader perspective of events than typically allowed by first-person narration.
Ms. MacElroy: Where were we?
Sheldon: And "ergo" is Latin for "hence," Derek.

Missy: What's it like to not believe in God?
Sheldon: It's great. Big fan.
Missy: Are you ever afraid you're wrong?
Sheldon: About religion? Never. About other things? Also never.

Adult Sheldon: That was the first time I held my father's hand. I wouldn't touch my brother's hand until seventeen years later, thanks to the invention of Purell.

Mary: You understand that some people are going to be intimidated by you, because of how smart you are?
Sheldon: Or maybe they'll recognize my intellect and make me their leader.

Sheldon: I smell ammonia. They must've done a thorough cleaning recently. I like that.