Sheldon: I've been doing some research on addiction, both the biochemical and behavioral aspects, and I think there's a problem with the current version of our lie.
Leonard: What are you talking about? It's fine. She bought it. It's over.
Sheldon: Sadly, it's not. Substance abuse is a lifelong struggle, but beyond that I have realized that the Leo I described would not have agreed to go to rehab.
Leonard: Why not?
Sheldon: Because Leo is a middle child.
Leonard: There is no Leo. How can you say that?
Sheldon: You didn't read the bio, did you? He's not just a middle child, he's the quintessential middle child, from a broken home to boot. Psychologically speaking, the attention he gets by rebelling even to the point of self-destruction is more emotionally valuable than the help he would get at rehab.
Leonard: I've got a solution.
Sheldon: Great, what is it?
Leonard: Get out.

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.

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: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Sheldon: I am uncomfortable having been included in your lie to Penny.
Leonard: What was I supposed to say?
Sheldon: You could have told her the truth.
Leonard: I could not have said that, it would have hurt her feelings.
Sheldon: Is that a relevant factor?
Leonard: Yes.
Sheldon: Then I suppose you could have agreed to go.
Leonard: What would I have said afterwards?
Sheldon: I would suggest something along the lines of "singing is neither an appropriate vocation nor avocation for you and if you disagree, I recommend you do a CAT scan to locate the tumor which is pressing on the cognitive processing center of your brain".

Sheldon: Leonard?
Leonard: Yes?
Sheldon: (Sarcastic) When we played chess earlier, you were terrific, and I can't wait to play you again. Goodnight!

Toby: Damn you, Chaplain Horrigan.
Penny: I'm sorry?
Toby: The Phillipines: 1992: The Subic Bay Naval Station: A young boy on the cusp of manhood. His only companions, mongrel dogs and malarial mosquitoes. Desperate and alone, he reached out to a man who promised to introduce him to a merciful, loving God. But instead introduced him to a gin-pickled tongue shoved down his adolescent throat. What choice did he have but to drink, shoot, and snort his pain away?
Sheldon: Don't forget genetic predisposition towards addiction.
Toby: That's never been proven.
Sheldon: There have been studies.
Toby: Not double-blind studies!
Sheldon: How could there be double-blind study? Who would be the control group?