Howard: Sheldon, why are you arguing with the DMV?
Sheldon: How else are they going to learn? Look, question 2, "When are roadways most slippery?" Now, okay, there are three answers, none of which are correct. The correct answer is, when covered by a film of liquid sufficient to reduce the coefficient of static friction between the tire and the road to essentially zero, but not so deep as to introduce a new source of friction.

Sheldon: Statistically, red cars are stopped by police far more often than any other color. I don't want any hassles with the fuzz.

Sheldon: No. I quit. [After Sheldon stands up, there is a crashing sound from the driving simulation. Then pained noises from animals]
Leonard: Aw, the pet store?
Sheldon: Remind me to compliment Wolowitz on the software, it's amazingly detailed.

Leonard: So wait,you're just gonna give up?
Sheldon: No, I'm not giving up. I never give up.
Leonard: So what is it you're doing?
Sheldon: I'm transcending the situation. I'm clearly too evolved for driving.

Leonard: Oh. It's Stuart.
Sheldon: You're not going to answer it?
Leonard: He wants to talk about Penny. I don't want to talk about Penny.
Sheldon: You're making an assumption. Perhaps the comic book store is on fire, and he needs your assistance.
Leonard: Why would he call me?
Sheldon: We don't know. And if you don't answer the phone, we can't know.

Sheldon: Answer the phone, Leonard.
Leonard: No! There, it went to voice mail.
Sheldon: Aren't you going to check your messages?
Leonard: No.
Sheldon: You have to check your messages, the leaving of a message is one half of a social contract which is completed by the checking of the message. If that contract breaks down then all social contracts break down and we descend into anarchy.

Leonard: Well, what are you gonna do?
Howard: I'm gonna figure out how to fix it, then I'll tell them.
Leonard: So, what do you need us for?
Raj: He can't figure out how to fix it.
Howard: Hey, you said you were gonna be supportive.
Raj: I'm trying, but you have to admit this is pretty damn funny.
Sheldon: I agree. It's the juxtaposition of the high-tech nature of space exploration against the banality of a malfunctioning toilet that provides the comic fodder here. Check your messages.

Raj: Okay, look. Instead of trying to reinforce this structure here, what if we just ran another line, bypass it entirely?
Sheldon: It won't work. The diameter of the tubing is insufficient.
Raj: What if we reposition the collection tank?
Sheldon: It won't work. No way to mount it.
Howard: Okay, here's an idea. What if I change my name and go live with my cousin and her husband Avi in Israel?
Sheldon: That could work.

Howard: Hang on, I think I've got this. Help me see if we can wedge this little piece of PVC behind the support rod.
Sheldon: You're overestimating the tensile strength of the substructure you're building.
Howard: Sheldon, I know what I'm doing.
Sheldon: If you knew what you were doing, there wouldn't be a space toilet where my coffee table should be.

Sheldon: You know, I also have a date tonight. But don't worry, it's not another woman. It's string theory.

Amy: Hi.
Sheldon: Hello.
Amy: What you doing?
Sheldon: Oh, taking another picture with my baby. Look how big he got!

Sheldon: I can't believe you hung up on me!
Leonard: What the hell? What are you doing here?
Sheldon: I am proving you wrong. I've been working back there for hours. You had no idea.

Penny: Okay, look, you have an office at work. Why don't you go there?
Sheldon: I can't go to the office every time I have a brilliant thought. I'd basically be living there.
Leonard: Sounds good, do that.

Amy: Look, at least if you watch it, maybe you can find more specific things to criticize.
Sheldon: Oh, that is a good point. Criticisms are more hurtful when they're specific.

Wil Wheaton: [on TV] Hey, everybody. I'm Professor Proton. Welcome to the show. Today I will be teaching you how to make a real hovercraft using common household items.
Sheldon: Darn it, I do like objects that hover.
Wil Wheaton: [on TV] All you will need is a CD, a bottle cap, a balloon, and some super glue.
Sheldon: Oh, no! I have all those things!