Raj: You're just jealous because it turns out I'm Penny's number two choice after Leonard.
Howard: Hey, if I wasn't engaged to Bernadette, that totally could have been me.
Leonard: Please. Sheldon would have been before you, and he might not even have genitals.

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?

Leonard: Well, uh, okay, um, I dont want to get back together with Penny. We tried it, it was crazy, it didn't work, but I can't deal with the fact that she slept with my friend Raj. And then I find out that Raj's sister Priya, who I've been going out with for eight months, is moving back to India. So I'm just completely confused and alone.
Beverly Hofstadter: I understand.
Leonard: Got any advice?
Beverly Hofstadter: Yes. Buck up.
Leonard: Excuse me. You're a world-renowned expert in parenting and child development, and all you've got is buck up?
Beverly Hofstadter: Sorry. Buck up, sissy pants.

Sheldon: For the record, I do have genitals. They're functional and aesthetically pleasing.

Amy: A guest in my trundle bed and a boy at my door. I wish I could tell thirteen-year-old me it does get better.