Mary: It's really coming down out there.
Sheldon: I don't believe it.
Mary: Oh, don't worry. I'm sure they fly in much worse.
Sheldon: What?
Mary: The rain. It's gonna be okay.
Sheldon: Oh, Dad told me you might get nervous. [taps Mary's hand] There, there.

Sheldon: Oh, I'm not nervous, I'm excited. There's a celebrity on the plane.
Mary: Really? Who?
Sheldon: Dr. Van Doornewaard.
Mary: Oh. Who is that?
Sheldon: You're kidding, right? He's the Dmitri Mendeleev of physics.
Mary: And he is...
Sheldon: Dmitri Mendeleev? Oh, he is to chemistry what Pierre-Simon Laplace is to...
Mary: Got it. He's a famous science guy.
Sheldon: Mm. Look at him, sitting in coach like a regular joe. I'm going to go introduce myself.
Mary: Uh, the seatbelt sign is on. I think we're getting ready to take off. [Sheldon grumbles] It's okay. He's not going anywhere.
Sheldon: Ooh, I'm going to have him autograph my vomit bag. I hope I don't have to use it first.

Sheldon: Now, do you think we're ever going to discover the equivalence of heterotic and supergravity string theories?
Dr. Van Doornewaard: You betcha. That would turn the theory of quantum gravity upside down.
Sheldon: Will anybody know?
Dr. Van Doornewaard: Was that a joke?
Sheldon: Yes. [both laugh]
Adam: Would you like to switch seats with me?
Sheldon: Oh, no, I wouldn't want to put you out. I'm spending the summer at the University of Heidelberg studying superstrings.
Dr. Van Doornewaard: Wonderful. I'm actually a visiting professor there.
Sheldon: Then I guess I'll be visiting a professor there.
Dr. Van Doornewaard: [laughs] Very good.
Sheldon: [to Adam] Get it? [laughs]

Sheldon: I brought you a wiener schnitzel.
Mary: Thank you.
Sheldon: I tried it. It's yucky.

Mary: Um... there was a tornado back home. Everybody's okay, but your meemaw's house was destroyed.
Sheldon: But everyone's okay, that's confirmed?
Mary: Thank God, yes.
Sheldon: You're thanking the deity who sent the tornado?

Mary: Honey, your meemaw lost her house.
Sheldon: I'm sure she has insurance.
Mary: That is not the point.
Sheldon: Well, what is the point? What would we do once we get there?
Mary: I don't know. Uh... be there, provide solace, lend a hand.
Sheldon: Me? Lend a hand? You're funny.

Mary: [on the phone] I need to change our return flights. As soon as possible.
Sheldon: What are you doing?
Mary: Uh... Tonight would be great. How much? [Sheldon hangs up the phone] Sheldon Lee Cooper!
Sheldon: I told you I'm not going home.
Mary: I am your mother. What I say goes. [Sheldon lays down on the couch] What are you doing?
Sheldon: Passive resistance. Good luck lifting my limp body.

Mary: [retching]
Sheldon: You know, sympathetic vomiting has an evolutionary basis. In the Paleolithic era, when one member of a tribe would start vomiting, it was a signal to the rest that they'd eaten something poisonous and... Oh, scooch. [retches] Like that. [retches] Another fun fact...

Sheldon: Oh, 7:19 to Frankfurt. Birthplace of the frankfurter. That's a must-see.

Sheldon: Auf wiedersehen.
Mary: Where you going?
Sheldon: Library. [whispers] In Frankfurt.
Mary: Have fun.
Adult Sheldon: As much as I hated lying, I loved trains just a little bit more.

Sheldon: [v.o.] Dear Missy, I'm currently on my fifth train ride exploring Germany and the nations of the former Austro-Hungarian Empire. It's often referred to as a dual monarchy because the Hapsburg ruler was both the emperor of Austria and the king of Hungary. Speaking of hungry... strudel.
[Sheldon steps off the train to buy a strudle from a cart. As a whistle blows, the train's engine hisses and it begins to pull away.]
Sheldon: Wait! Wait! Warten! Warten! That's German for "wait"!
Adult Sheldon: As you can see, they did not warten.

Officer #1: It's okay, young man, we speak English.
Sheldon: But not as well as my German, so stay with me.

Mary: What happened to you?
Sheldon: Tough day.
Mary: At the library?
Sheldon: Yes.
Mary: Where's your other shoe?
Sheldon: When I was leaving... the library, a wild dog attacked me.
Mary: Oh, sweetie, no.
Sheldon: I fought him off, but at the price of a loafer.
Mary: Where's your backpack?
Sheldon: I guess he got that, too.
Mary: Well... that all makes sense, Sheldon, if that's what really happened.
Sheldon: It is.
Mary: Okay, then. Why don't you go lie down?
Sheldon: I will. I'm tired from all the things that happened...
Mary: At the library.
Sheldon: At the library.

Mary: Excited to be going home?
Sheldon: [points to his head] This is home. I'm always here. But I am excited to share everything I've learned with my colleagues.
Mary: That's nice.
Sheldon: Scientifically speaking, they're savages covered in their own filth, and I'll be bringing them the light.
Mary: There's probably a nicer way to say that.
Sheldon: Oh, there is. But if a summer in Germany has taught me anything, it's that brutal honesty is its own kind of love.
Mary: I'll crochet that on a pillow.
Sheldon: Mm.

[Sheldon is holding his nose and puffing his cheeks out:]
Mary: What're you doing?
Sheldon: Trying to get my ears to pop.
Mary: Want a piece of gum?
Sheldon: Is it cinnamon gum?
Mary: Yeah.
Sheldon: I have enough problems. [baby cries] Oh, you've got to be kidding me.