Which house would you not want to be in and why?

Gryffindor.
There's no way I'd want to be a gryffindor. Sure they have a couple of decent qualities. They're brave, for starters. But they lack discipline, they're arrogance goes unpunished and the worst part is they get rewarded for insubordination cause Hogwarts professors are partisans. And Dubbadore made some last minute changes in the first year and stole the house cup which was originally Slytherin's. They wear that proud lion badge and walk about like they owned the castle but Snape saw Gryffindors for what they are...a bunch of thieves...

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Slytherin--they are creepy!

Slytherin, because unfortunately a fairly large percentage of the students in the house are fairly unpleasant.

Slytherin. Because they have this fascist ideology about them and produce the most evil wizards. So, yeah, no thank you.
The second house I was never too keen on was Hufflepuff, which is exactly the one I got in the Pottermore test. At least 'we're' kind hearted.

Slytherin because I'd probably have to bunk with people like Millicent Bulstrode and Pansy Parkinson.

Earth without art is just "eh."

I have to go with Slytherin as well. Even if we ignore the pure-bloodism and snobbery, that is very common among these people, all of them seem to be mean bullies, annoying bitches or self-righteous goths. Even as JKR started giving the Malfoys and Snape character developement in the later half of the series, so that we wouldn't hate them, it is hard for Slytherin to get rid of their reputation as "the evil house". And the only two nice Slytherins seem to be Horace Sloghorn and Andromeda Black Tonks (and we don't know for sure that she even was in Slytherin).

I guess that Hufflepuff wouldn't be my first choice either, but they at least seem to be mostly kind enough people. But I would probably have been a brainy Gryffindor, like Hermione. Unless I got into Ravenclaw, of course. 

Intelligence and purity.

Ravenclaw - I couldn't stand having to be around those type of people all the time.

Ravenclaw - I couldn't stand having to be around those type of people all the time.