Iris scanner: Leonard Hofstadter. Access granted.
Leonard: Hmm. I don't care if this thing's burning out my retinas; it makes me feel special.

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?

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: And just remember, I am proud of you and I support you in all that you do.
Amy: Thank you. That means a lot.
Sheldon: Oh, and one last thing. If you find yourself working with a male scientist who's as smart as me, as tall as me and has hair like Thor, well, then I want you to step away from the situation and call me immediately.

Raj: I really can't thank you enough for taking me in. You know, I was in a pretty low place in my life, and-
Sheldon: (from across the hall) Oh, Amy, you naughty vixen.
Raj: Anyway, uh, as I was saying, I was at a pretty low place in my life and, uh, if it wasn't for friends like you-
Amy: (from across the hall) My goodness, that form of stimulation is highly efficient.
Raj: I can't compete with that.

Howard: Well, why would you do that?
Colonel Williams: You guys completed phase one, we'll take it from here.
Sheldon: Where did you move it?
Colonel Williams: I can't tell you that.
Leonard: Are you implementing phase two?
Colonel Williams: I can't tell you that.
Sheldon: Wait, so you're just going to take all the work we've done for the last year and toss us aside?
Colonel Williams: That one I can tell you, yes.
Howard: This is all very upsetting.
Colonel Williams: I'm sorry to hear that. As you know, the primary focus of the United States military is people's feelings.
Sheldon: If that's sarcasm, please save it for our enemies.