Cyromancers hitting you with three Ice Spikes consecutively causing your character to simply run on the spot. It's absolutely infuriating. Besides those nothing really bothers me, which is pretty rare in a game for me, usually I get annoyed and hate every enemy.
I can't believe I forgot about ice mages. They are the worst! They die pretty easy but getting to them is the real challenge. They always slow me down with their damn ice spells and to make it even worse they backpedal while casting. I don't know why but most ice mage bosses one shot me. Even my nord character. I wish the players destruction was as strong as the mages you encounter. They need to make destruction scale so we don't have to depend on impact and enchantments.
1. Slaughterfish: So now the game says I'm in combat preventing me from doing anything else... waiting, mining, sleeping, etc because there is a fish in a nearby pond who is completely incapable of hurting me

. Now when I decide to kill him I have to stand in the water till he comes up to me and kill him without taking a step forward because then I'm swimming and can't fight..... I have found that flame cloak just before you get in the water is a great way to fry these svckers.
2. Anything that casts disarm shout. What I really want to do is wonder around looking for my enchanted sword in a dark dungeon. Thanks!!!
3.

I have to kill them... because the game records how many I kill separate from everything else. But they are so small and bouncy that they can be hard to hit!
Yeah, Slaughter fish are pretty pointless imo. If you want me to fight an enemy in the water at least make it like a giant sea creature or something fun and challenging. It's very annoying when I can't fast travel because one is around.
Disarm shout is ridiculously annoying as well. I have to reload my saves all the time because I can never find my weapon. It's fun to use on enemies but its a pain when used on you.
LOL, I recently found out the game records the bunnies you kill and I try to kill as many as I can now. I always use a bow to make it more of a challenge though.