"Well, that was rude." 

"I don't," said the Hat, in his most pointed voice, "disagree with you about that." Really, she was plenty rude, as most people who were alone for ten long years would be. And, as it happened, she was a bit addled.  

"I wonder what darker things are moving, though. Oh, what do you suppose a boggart changes to for a troll? Or a vampire? Oh, a vampire is likely just the sun or some other nonsense that will kill them. Much less interesting. But a troll, I do wonder what they fear. Fire will shoo them off, but it will shoo most folks off if they do it right. That shouldn't be the thing they fear most. Oh, I hope the boggarts eventually migrate to them. Or they migrate to the boggarts. I would love to see what happens." 

"I guess it depends on the troll, eh? Most trolls would be Sorted into Hufflepuff, did you know, but you would certainly get some Gryffindors amongst them - not so much Ravenclaws or Slytherins," said the Hat, now feeling chattier. "Human complacency, you know. Most people do think other species are all rather monochromatic! As for those darker things, I don't know. The mandibles don't know either - this is why it is alarming, and why I'e been sent to bring others back. We're going to need all the help we can get. And you, you could be useful. Impolite, but useful. Paranoid, but useful. INSANE, but useful!"