Sheldon: So, can you get it working?
Howard: I'm an MIT-trained engineer. I've built components for the space station.
Sheldon: I thought the zero-gravity toilet didn't work.
Howard: It worked fine. It just wasn't designed for Russian cosmonauts and their potato-based diet.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Josh: So, I have to ask, was the robot sexy?
Howard: It was actually just a mechanical hand.
Josh: 'Cause that's all you need, right?
Howard: You are my brother.

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

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.

Leonard: So, for the remainder of my speech, this is for the invisible kids. Maybe you never fit in. Or maybe you were the smallest kid in the school. Or the heaviest. Or the weirdest. Maybe you're graduating and you still haven't even had your first kiss. By the way, nineteen, and Geraldine Coco, wherever you are, thank you. Maybe you don't have any friends, and guess what, that's okay. While all the popular kids are off doing whatever - I don't know what they're doing because I was never there.

Howard: All right, playtime's over. Let's open this baby up.
Sheldon: Won't that void the warranty?
Howard: Sheldon, I have a master's degree in engineering. I wipe my bottom with warranties. Except for AppleCare. That pays for itself in the long run.