Ruffnut's look of confusion only got more and more dense as Hiccup explained the basics of their new situation. At the part about the world being a ball she snorted in derisive objection. By the end of it she threw her hands in the air.

"Yeah alright sure! Why not? Because clearly I've gone insane and you've tied me to a boat and sent me out to sea. This is all just some kind of weird crazy dream thing. There is no way I just heard the smartest guy I know tell me there's a man on the moon, the world is round, and that we have a magic globe."

Because the alternative was...what exactly?

"Is Astrid at the base? I need someone closer to my level." Which meant to say Hiccup was too smart for her to follow other then blindly.