George: Hey. What you doing?
Mary: The twins' first birthday. Look how little they were.
George: Well, look how little I was.
Mary: And Georgie when he lost his first tooth.
George: When he learned it was worth a quarter, he tried pulling the rest of 'em.
Mary: Guess he's always been a businessman.
George: He ain't an idiot.

George: And Sheldon's fine. You know what he's like. If someone took him, I'm sure they'll bring him right back.

Georgie: A bill? Really?
George: Room and board, buddy.
Georgie: $50 a month for food?
George: The way you eat, I should've gone $50 a week.
Georgie: Laundry services?
George: Your poor mother has to touch your underwear.
Georgie: What's the $10 a month "peema" charge?
George: Oh, P-I-M-A, that's a "Pain in My Ass" tax. My way of getting compensated for you taking years off my life.

Georgie: You know what else is nice?
George: Hmm?
Georgie: I get to learn from all your parenting mistakes.
George: I'm starting to think letting you live this long was one of 'em.
Georgie: Like that. I'd never say something so awful to my kid. [George scoffs] Thanks, big guy.

Adult Sheldon: I always believed my extraordinary life would be chronicled in numerous biographies. I even used to make up my own titles. My favorites were: "From Texas to Success: the Sheldon Cooper Journey", and "Cooper for Kids", a pre-school introduction to quantum gravity in superstrings. The point is, I knew my formative years would be well-documented, which meant I needed to polish up some of my early academic credentials, especially East Texas Tech.

Sheldon: If W is the Kähler metric on the algebraic variety X, and the canonical bundle KX is trivial, then X is what?
Dr. John Sturgis: A Zariski space.
Sheldon: Wrong. [slaps Dr. Sturgis's hand with his pencil]
Dr. John Sturgis: Hey!
Dr. Linkletter: Obviously, it's an elliptic curve.
Sheldon: Wrong. [slaps Dr. Linkletter's hand with the pencil]
Dr. Linkletter: Hey!

Dr. John Sturgis: Why are you hitting us?
[flashback:]
Mei-Tung: Wrong.
Sheldon: Ow! Why'd you hit me?
Mei-Tung: Pain is the best teacher.
[present:]
Sheldon: I'm teaching you.
Dr. Linkletter: Well, it feels like you're hitting us.
Sheldon: Like you, I struggled with these concepts, but eventually, I mastered them, through hard work, resilience and a healthy dose of knuckle whacking.