Which character's house makes the least sense?

I'm not talking about edge cases like how Hermione could have been a Ravenclaw, I mean times where the sorting hat seemingly just got it completely wrong.

I'll go first - Dumbledore. I really do not understand why he was in Gryffindor. His long convoluted plans and habit of keeping his cards close to his chest are the epitome of Slytherin behavior. You could also get away with saying Ravenclaw because of how academically gifted he was, but I do not see any Gryffindor traits in him except for the fact that almost every Order member was in that house. It's not like his house alignment even matters, because it's only ever brought up once, so I don't see why he needed to be in Gryffindor.