Leonard: You cannot possibly be that arrogant.
Sheldon: You continue to underestimate me, my good man.

Sheldon: You just lied to Penny.
Leonard: Yes, I did.
Sheldon: And you did it so casually. No rapid breathing, no increase in perspiration.
Leonard: So?
Sheldon: So, lack of physiological response while lying is a characteristic of a violent sociopath.
Leonard: Sheldon, are you worried about your safety?
Sheldon: No. I imagine if you were going to kill me, you'd have done it a long time ago.

Howard: So, road trip to Long Beach.
Leonard: No, we're not going to Long Beach.
Raj: Why not?
Leonard: Because Sheldon doesn't have a drug addicted cousin Leopold.
Raj: Oh, too bad. I've always wanted to go to Long Beach.
Sheldon: It's a very nice community. The Queen Mary is docked there. Once the largest ocean liner in the world, it's now a hotel and restaurant where they host a surprisingly gripping murder mystery dinner.
Raj: Sounds fun.

Sheldon: Well, as I predicted, I am sick. My fever has been tracking up exponentially since 2am, and I am producing sputum at an alarming rate.
Leonard: No kidding?
Sheldon: No. Not only that, it has shifted from clear to milky green.
Leonard: Alright, well, get some rest and drink plenty of fluids.
Sheldon: What else would I drink? Gasses? Solids? Ionised plasma?

Howard: It was Sheldon.
Leonard: I tried to stop you.
Howard: It's my own fault. I forgot the protocol we put in place after the great ear infection of '06.

Penny: Sheldon, you are a grown man, haven't you ever been sick before?
Sheldon: Well, of course, but, not by myself.
Penny: Really, never?
Sheldon: Well, once. When I was fifteen, and spending the summer at the Heidelberg Institute in Germany.
Penny: Studying abroad?
Sheldon: No, visiting professor. Anyway, the local cuisine was a little more sausage-based than I'm used to, and the result was an internal blitzkrieg with my lower intestine playing the part of Czechoslovakia.

Howard: I guess times have changed since we were young. Smart is the new sexy.
Leonard: Then why do we go home alone every night? We're still smart.
Rajesh: Maybe we're too smart. So smart it's off-putting.
Howard: Yeah, let's go with that.

Sheldon: Here's the problem with teleportation.
Leonard: Lay it on me.
Sheldon: Assuming the device could be invented which would identify the quantum state of matter of an individual in one location, and transmit that pattern to a distant location for reassembly, you would not have actually transported the individual. You would have destroyed him in one location, and recreated him in another.
Leonard: How about that.
Sheldon: Personally, I would never use a transporter. Because the original Sheldon would have to be disintegrated in order to create a new Sheldon.
Leonard: Would the new Sheldon be in any way an improvement on the old Sheldon?
Sheldon: No, he would be exactly the same.
Leonard: That is a problem.

Leonard: So, Dennis, how long have you been in America?
Dennis Kim: A year and a half.
Leonard: No kidding. You speak English really well.
Dennis Kim: So do you. Except for your tendency to end sentences with prepositions.
Leonard: What are you talking about?
Dennis Kim: That.
Sheldon: He's not wrong.

Howard: I've been at this lab for three years, you've never came by to say hello.
Sheldon: Well, up until now I've had better things to do. So, what are we making today?
Howard: A small payload support structure for a European science experimental package that's going up on the next space shuttle.
Sheldon: Really, how does it work?
Howard: When this is done, it will be attached to the payload bay, and the sensor apparatus will rest on it.
Sheldon: Uh, huh. So it's a shelf?
Howard: No, you don't understand, during acceleration it needs to stay perfectly level and provide ... yeah, okay, it's a shelf.

Sheldon: I need my wrist brace. All this button pushing is aggravating my old Nintendo injury.

Penny: Oh, please, it's not a time machine, if anything, it looks like something Elton John would drive through the Everglades.
Sheldon: It only moves in time, it would be worse than useless in a swamp.

Sheldon: Oh, no, not Morlocks, not flesh eating Morlocks! Help!

Sheldon: Leonard, it's two in the morning.
Leonard: So?
Sheldon: So, it's my turn.

Sheldon: Why did you set it for the day before yesterday?
Leonard: Because I want to go back and keep myself from getting a time machine.
Sheldon: You can't. If you were to prevent yourself from buying it in the past, you would not have it available in the present to travel back and stop yourself from buying it, ergo you would still have it. This is a classic rookie time travel mistake.