As for things I hate-
deposts (tend to be both)
badly abusive family members
I take the word hate very seriously. I don't even hate our spammers (the real ones, not the bots). If I say the word hate in a serious conversation, it means I'm willing to put a bullet in them. Hence, I rarely use it seriously.
For all the previous stuff everyone has listed, that ranges from annoying to anger, and occasionally into rage territory, but you have to be a bad guy on L&O: SVU or Criminal Minds to get into the hate range.
There is one other category, but I'm not bringing it up because it treads on what may be controversial grounds. And this is not the forum for that discussion.
I take it very seriously, too. The only crimes that I think are never justified are forcible rape and maybe child molestation. I do not consider it molestation when it's just an age of consent thing, when the "victim" is 16 and the other party is not only having a romance with he or she but is just 19, his or herself. If there's force or even trickery involved, I call it rape but then, that would apply to an adult, too.