Minimus:
There isn't any one belief, but lots and, in fact, too many to list. But, some of their "beliefs" are subjective views of scriptures, others are cultural within the religion. All the posts above are on the mark. However, these are mine.
For one, I never believed that I was responsible for other people being saved. Truly ridiculous. Well, who was responsible for me being saved? This is nothing more than a guilt-trip to get people enslaved in a never-ending preach, preach mode. If you ask me, I think this promotes neurosis.
I also never believed the JWs fulfilled any bible prophecy. Even when I was studying, this never sat well with me but I kept my mouth shut.
The claim that they have no clergy class, when, in fact, they have a plain clothes clergy with titles. They also try to say the average rank and file JW is a "minister". Well...then it would appear that their religion has several tiers of "ministers". I don't accept any of them since I joined on the premise that they had "no clergy class".
I never believed anybody's divine claims and always felt people who claim to be anointed or whatever were looking for some special attention or "respect". They never got any from me. Sorry, but I never bought any of this. I also never believed the religion communicated with God in some way. Well, prove it.
I also wasn't there to placate overly-sensitive people.
I never believed in deliberately living on the edge in order to pioneer and imagining other people were there to give you handouts. I refused to quit my full-time job and am thankful I never followed their bad advice.
The JW religion talks out of both sides of their mouth on this issue and now the religion is filled with trouble in this bad economy with too many categories of "needy" people.
Last but not last, their views on women. None of those idiots there was my "head" and I made sure I kept them at a distance since they don't respect boundaries.