Leonard: You know, I do understand what you're feeling. My brother and sister's accomplishments have always been held over my head.
Sheldon: How did you deal with it?
Leonard: I wet the bed until college, but I don't think that's a quality fix.

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.

Howard: What do you think?
Barry Kripke: That ... is ... hilarious! Give me the remote control. I want to drive him into the girls' restroom.
Howard: All right, we're done. It's offensive.

Amy: Bert is studying the way microbes in rocks can survive in extreme environmental conditions.
Leonard: They say it could be a potential indicator of life on other planets.
Penny: You know what, I've met Bert. Isn't he an indicator of life on other planets?
Sheldon: You used to make those jokes about me. Now everything's Bert, Bert, Bert.

Raj: Well, I'm glad to see you moving forward.
Sheldon: Bert did quality research. And he deserves whatever accolades he receives.
Howard: What is going on? (To Leonard) Did you upgrade his software last night?
Leonard: I think he might be learning on his own.
Raj: Then the robot uprising has begun.