User blog comment:HumboldtLycanthrope/Werewolves/@comment-25947144-20170310140210

Werewolves are about one of the biggest nightmares you could come up with. Humans and wolves are two of the best hunters on the planet, big part of the reason why we domesticated them. For many, humans are very frightening things. Not easy to predict, smart, persistent and extremely adaptable. Now take the only parts of him that stop him from harming you, his morality and rationality, and replace that with the purely animistic instinct of a wolf and add their natural hunting abilities together.

Also interesting that you mentioned Wendigos. They do a similar thing, except instead of replacing morality and rationality, they just fade away as darker elements of humans are accentuated. Obsession, desperation, insatiable hunger and constant torment. And it isn't exactly a temporary change, either.