Mary Cooper: You know, you two make a cute couple.
Leonard: No, no we're not, we're not a couple, we're single, two singles, like those individually wrapped slices of cheese that are friends.
Mary Cooper: Did I pluck a nerve there?
Howard: Oh yeah.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

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.

Mary Cooper: You don't hunt, do you?

Mary Cooper: I'm sorry, did I start that sentence with the words, "If it pleases your highness?"