Mary: Well, we are so happy to babysit. In fact, if you want to go to dinner after the movie, that's fine with us.
Mandy: Aw, thanks, but we're trying to save money.
Mary: George, give them some money so they can go to dinner.
George: [quietly] We're already babysitting for free.
Mary: But we never get to see this little one, because her mean Mommy and Daddy moved her away.
Mandy: Well, Mommy and Daddy have their own bathroom now, so...
George: Oh, that's the dream right there.

Sheldon: Regardless, I'm not interested in making any more friends.
Mary: Oh, I don't think that's how you really feel.
Sheldon: It is. From now on, it's a hermit's life for me.
Mary: I bet, when you grow up, you will be surrounded by lots of smart, wonderful friends.
Sheldon: I can't see that happening.

Sheldon: Mom, when should I be expecting my testicles?
Woman: [turns around] What is wrong with him?
Mary: Nothing is wrong with him. Now turn around before I knock your lights out.
Sheldon: Hello.

Sheldon: And then they laughed at me for not knowing something that they knew. Who does that?
Mary: You do.
Sheldon: Well, this is no time for a teachable moment. Your child is hurting.
Mary: Sorry. [taps Sheldon's shoulder] There, there.
Sheldon: I guess that'll do. Now, how about a hot beverage?

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.