It's hard to imagine something permanent enough to be hell, really...I mean, you'll desensitize to anything given the chance. Familiarity breeds contempt, after all. A lot of things would be hell for me, but I'd get used to them given enough time...probably. After a while you just stop noticing and just bear with it, because it has to end some time...and even if it doesn't, you can adjust so you don't notice it.
Hell is constant, unpredictable, unpleasant and uncontrollable surprises. Things you CAN'T get used to, because you don't know what is coming or how you're going to react. Not being able to process and adjust, but being forced to react - or not even being given the chance to - to anything and everything.