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.

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

Professor Proton: Can I ask you a question?
Leonard: Yeah, sure.
Professor Proton: Why do you put up with Sheldon?
Leonard: Oh, you know because we're friends.
Professor Proton: Why?
Leonard: Wow, you ask really hard questions. Look, I know he can be aggravating, but what you have to remember is he's not doing it on purpose, it's just how he is. But he's also loyal and trustworthy and we have fun together.
Professor Proton: You know you're describing a dog?
Leonard: He did bite me once. But in his defense, I came up behind him while he was eating.
Professor Proton: They hate that.
Leonard: Sheldon is the smartest person I have met. He's a little broken and he needs me. And I guess I need him too.
Professor Proton: Why is that?
Leonard: Boy, you will not let this go, will you?

Sheldon: I've changed. Like the frog who's put in a pot of water that's heated so gradually, he doesn't realize he's boiling to death.
Penny: Or you're the frog who's been kissed by the princess and turned into a prince.
Leonard: Or you're just a tall, annoying frog.

Amy's Mom: It's nice to meet you too Sheldon, I honestly didn't believe Amy when she told me she had a boyfriend.
Sheldon: I assure you, I am quite real and I'm having regular intercourse with your daughter.
Amy's Mom: What?
Sheldon: Oh yes, We're like wild animals in heat. It's a wonder neither of us has been hurt!
Amy's Mom: Amy? What is he saying?
Amy: You wanted me to have a boyfriend, mother, well here he is! Have to sign off now. My hunger for Sheldon is stirring in my loins.
Sheldon: Oh yes. It's time for me to make love to your daughter's vagina.

Sheldon: We no longer live at 2311 Los Robles, we live at 311 Los Robles. *Holds up number 2 fixture*
Leonard: You changed the address on the building? What about mail?
Sheldon: No worries, I explained our predicament to our letter carrier. He was sympathetic, his exact words were "Got your back Jack. Bitches be crazy!"

Leonard: Have you considered telling her how you feel?
Sheldon: Leonard, I'm a physicist, not a hippie.