Sheldon: Thanks for carving a smiley face in my grilled cheese sandwich.
Mary Cooper: Well, I know how to take care of my baby. His eyes came out a little thin, but you can just pretend he's Chinese.

Mary: He gets his temper from his daddy.
Leonard: Ah.
Mary: He's got my eyes.
Leonard: I see.
Mary: All that science stuff, that comes from Jesus.

Sheldon: Well, this is confusing for me. But I don't want to stand in the way of your happiness. So, I will condemn you internally while maintaining an outward appearance of acceptance.
Mary: That is very Christian of you.

Sheldon: I'd like you to meet Oppenheimer, Frisch, Panofsky, Feynman, Weisskopf.
Mary: Yeah, I get it. You got a lot of cats, and you gave 'em cute Jewish names.

Howard: Sheldon, you remember the first few weeks we were looking for magnetic monopoles and not finding anything, and you were acting like an obnoxious, giant dictator?
Raj: I thought we were going to be gentle with him.
Howard: That's why I added the '-tator'.

Sheldon: Hello, Penny. I realize you are currently in the mercy of your primitive biological urges. But, as you have an entire lifetime of poor decisions ahead of you, may I interrupt this one?

Sheldon: But evolution is not opinion, it's a fact.
Mary Cooper: And that is your opinion.
Sheldon: [to Leonard, Howard and Raj] I forgive you, let's go home.