Sheldon: I understand why you're upset. You're afraid that costume makes you look fat.

Sheldon: Radio contact is sufficient. No need to extend your middle finger.

Sheldon: Clearly febrile delirium is setting in. Please bring me some soup while I still understand what a spoon is for.

Sheldon: Amy, this isn't easy to say. All relationships are difficult. But even more so when you're with a person who struggles with everyday social interactions. And frankly, who can strike people as being kind of a weirdo.
Amy: Sheldon, you're not a weirdo.
Sheldon: I wasn't speaking about me. I mean, honestly, there's no telling what will set you off. Introducing myself as your boyfriend. Giving you the opportunity to drive me home. Breaking the ice with you colleagues using ethnic humor - the funniest kind of humor.

Sheldon: On the contrary I find the Grinch to be a relatable and engaging character. And I was really with him, right up to the point that he succumbed to social convention, returned the presents and saved Christmas.

Raj: Did you go to your prom?
Sheldon: No. I had a date with a proper education. Instead of a tuxedo, I dressed myself in good habits. Instead of spiked punch, I enjoyed the intoxicating flavor of knowledge. Instead of dancing in a gym, I shook my bootie to the seductive rhythms-
Penny: Okay, okay.
Sheldon: -of AP calculus.

Sheldon: Hi little guy. How'd you like to come home with us? You'll be living with me, because we don't live in the same house.
Amy: But that's not your fault. Like you, we're taking it ridiculously slow. You'll stay with me when he's away for Comic-Con or with work.
Sheldon: Or if they accept daddy's application to live on Mars.

Sheldon: And to think, I was about to waste the last of my good haemorrhoid cream on you.

Sheldon: I'd like to say I'm very happy that you're back together. And if I can figure out a way to do so and sound sincere, I will.

Sheldon: As a mental exercise, I invite you to figure out why the two of us can't play three-person chess.

Sheldon: I do feel obligated to point out to you that she did not reject you, you did not ask her out.
Leonard: You're right. I didn't ask her out. I should ask her out.
Sheldon: No! No that was not my point. My point was don't buy a cat.
Leonard: No, but you're right, I should march over there and ask her out.
Sheldon: Oh, goody! We're getting a cat.

Leonard: I don't think I can go to the North Pole.
Sheldon: OK, Leonard, I know you're concerned about disappointing me, but I want you to take comfort from the knowledge that my expectations of you are very low.

Sheldon: Why does everyone suddenly wanna talk to me alone? Usually nobody wants to be alone with me.

Sheldon: Oh Amy, I've never been touched like this before.

Sheldon: I couldn't sleep knowing that just outside my bedroom is our living room and just outside our living room is that hallway and immediately adjacent to that hallway is this!
Leonard: Do you realize if Penny wakes up there's no reasonable explanation to why we are here?
Sheldon: I just gave you a reasonable explanation.
Leonard: No, no. You gave me an explanation. Its reasonableness will be determined by a jury of your peers.
Sheldon: Don't be silly. I have no peers.