Mary Cooper: Shelly does not like change.
Sheldon: True. But all the clenching in the world will not keep testicles in your abdomen.

Raj: I don't like bugs, okay. They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

Mary Cooper: When your mom gets back, I'm gonna need to apologize for the way I spoke to her.
Penny: Well, come on, she did kinda start it.
Mary Cooper: Doesn't matter. A good Christian would have turned the other cheek. On the other hand, a good Texan would have shot her, so I'll just split the difference.

Penny: Leonard, what time does your mom's plane get in?
Leonard: I don't know. Sometime tomorrow morning.
Penny: Don't you want to know for sure?
Leonard: No need to. As soon as she flies into California airspace, I'll feel a disturbance in the Force.

Leonard: Not once did my mother ever give me any love or affection for just being myself. I always had to earn it.
Mary Cooper: Oh, Leonard, I'm sure she loves you very much. In her own cold godless way.