Hagravens. They just spam Fireball. It feels like I'm dueling some fat kid in WoW. Enrages me and I end up shooting extra arrows in them even after they die.

mud crabs acting all craby like

Frost mages

I found the easy way to kill them was to use Flame Cloak. Whenever they attack you they kill themselves.

I'd say the Frost Dragon annoys me the most because when he breaths at you it turns the screen black, you slow down and if you are not careful you end up getting chomped on. Even hiding behind something doesn't protect you it seems as your health drops like a waterfall no matter if you have a resist frost/cold spell active.

Dragons that refuse to land... I'm a Nord warrior and don't yet have Dragonrend. My archery is pretty weak. I can make fairly quick work of them once I ground them, but before that it's a bit tedious.

Spriggan matron... I've run into just one, but it killed me a couple times.

Ice Wraiths used to be really annoying.

Ice mages.

This

All animals, because playing as a mage, i somehow always get backstabbed by this random idiot beast while running through the wilds. and my health goes down a huge notch, and im like "IM GONNA DIE"
Also i hate ice wraiths, they being "ice" against the white snow background, plus their annoying flitting around makes it hard to discern where exactly are they :spotted owl:

I really dont care for Spriggans , you beat them to death, then they crouch down & then stand up with an almost full health bar. And they drain life from quite a distance, as well as having control over another one of my nemesis, the cave bear :violin:

Dragon priests because they have tonnes of health, unlimmited mana, and they steal your atronaches from you, and they float backwards faster than you can freakin sprint forwards.

A little off topic but ya i wan't a spriggan companion... can't wait for the CS which is now the CK i guess like geck.

Giant frostbite spiders because they disturb me (though not enough for me to want them removed from the game), and high level frost mages. My 50% frost resisting Nord even has two 20% magic resistance enchants, and they still manage to drain all his ~300ish stamina in a few hits. At least I can heal it all back in one dual cast, but if I don't have a follower/minion to help me they can take forever and a day to kill (coupled with other fire/shock mages I have to spam potions to survive).

mages, god I hate mages

Bears, Saber-Toothed Cats because both of them are fast and scary.
Draugr Overlords because they can FUS RO DAH me to the ceiling and then while my snail slow character tries to stand up they chop me to pieces...
Also spiders because they keep splitting at me... but they are easy to kill.

forsworn.

Poor little cecillo

Cheers

Spriggans annoy the hell out of me.

Icetrolls are my bain.. They seem to take more than dragons and hit me harder.. Buggers..

If you mean the ones escorting the prisoner,I killed them.I almost died a dozen times though.I led them on to the the rampart of the ruin they were beside.I basically ran in circles on the wall,ducking destruction magick,healing,and hitting and running until they all died.I couldnt understand why they didnt heal but whatever.Gorilla warfare ftw.Couldnt find the prisoner afterwords though.

Bears/sabre cats...mainly because I still don't get WHY I'm a Dragon/Undead lord killer that have to run like a girl from a wild animals that 2shot me...
Blood Dragons breathing ice...
Ice Wraiths

bears
all kinds of them
cave bears snow bears etc
one or 2 I can usually handle
but when there's more they simply have more health than I have mana
and there's no way in hell i can beat them at melee
so I have to get creative and use iceform or something
that or run away screaming like a little girl

they're not the toughest enemy in the game or anything
but the fact they can pop up pretty much anywhere at any time makes em really annoying
at least draugr death lords and such have the decency to hide deep in dungeons XD

Hagravens are the devil. Worst enemy for me by far, machine gun fireball spell.

Draugr Deathlords are a pain in the ass.

Hagravens are only easy when you get to close range with them and they don't cast fireballs.

Wispmothers are just plain hard. I had my ass pwned when I saw one for the first time.

Ice Wraiths are a bit hard to hit and having two of them can be troublesome, but they're quite easy otherwise.

Hagravens are easy.... I just sneak and [censored] them with my bow.....
That first dragon you kill in Whiterun.... It's impossible. I am level 54, and I still can't kill it......

Most recently the Bounty Hunter makes that top list of most annoying.

1). that damn piece of crap came at me while I was in sneak mode completely hidden, still knew where I was though.

2). after I told him to **** off, ran away and hid myself he STILL ran straight at me knowing exactly where I was.

3). being a sneak type with poor toe 2 toe combat abilities I couldn't fight him as one power attack was 1ohk and 2hk with normal attacks.

Bounty hunter knew where I was all the time, when outside of combat he would run straight at me even when I was hidden(after running about half way across the map) no opition to pay him off anymore once he got close enough he'd draw his axe and inch closer to me, i'd try to get in close for a strike but he'd turn around knowing I was there and grrrrrr.... so annoying that one, I ended up pelting him with arrows for a good 5-8 minutes...