Time for a rant thread to let out all of your frustration, but let's try to make it constructive at the same time so it might be somewhat useful information for ZOS.
1. You know what really grinds my gears?
Delayed to the extreme ultimates
I let my ultimate loose during a battle, 15 secs later I die, end up at the wayshrine and this happens

2. You know what really grinds my gears?
"Helping" hands
You'll be killing some easy mobs, no problem, then some Hero blows them up with an ultimate, as if to say, "I got your back bro". Seriously.. let me kill my own mobs. I don't care if you go ahead of me and clear the entire cavern with your steel tornado, just let me finish the ones I'm killing ffs.
3. You know what really grinds my gears?
Forced group world bosses
This should be optional - Solo or Group. I can NEVER find any one to do bosses with, so I literally have zero complete. I got through the first wave of Spheres at that Nyz-something-rather, and thought YES! Then another wave came out and blew my face off.
To be honest, I got further than the VR16 guy before me. He turned up, threw down caltrops and insta-died. I think he logged off in shame.
The point here is, if you're going to have achievements with cool costumes, please, PLEASE don't make it mandatory to have a group. Yes, yes, I understand this is an MMO, but some of us still prefer solo so we don't have to rely on others. I just like to get stuff done instead of waiting hours for help.
4. You know what really grinds my gears?
Snares, and that ridiculous unblockable root thing NPCs do
So OP. Nothing else to be said here. I now see why Stampede is pretty hot right now.
5. You know what really grinds my gears?
Pernickety chesters
Oh, you found a chest? That's awesome! Wait, why did you leave it open? Don't walk away. Please clear it so it can respawn. No? kden.
Yeah, you know who I'm talking about.
6. You know what really grinds my gears?
Eat-my-dust public dungeon rushers
Nightblades that cloak through hordes of mobs, or those sorcs that streak right through them, all the while my DK slowly drags his feet behind clearing the entire path solo. I'm sorry, but I hate these guys. Maybe it's envy of their mobility, or just the fact they leave me to clean up the mess that I find sickening, but yeah.. I don't like it.
7. You know what really grinds my gears?
Jumping
I hate you.
8. You know what really grinds my gears?
DK Chains
I want to love this spell, I really do. When it works, it's great.. but some times I just stand there jolting like an idiot and nothing happens. I can deal with the fact the target gets free immunity, I can even deal with the fact it's not as good as a true gap closer and can be dodged easily, but please just make it do something 100% of the time so I'm not doing some kind of weird dance.
9. You know what really grinds my gears?
Stagnant Stamina gameplay
My two stam builds are a DK and Sorc. They don't have any class related DD abilities, so the setup is almost identical. It's boring, so I go back to my Magicka DK, and then I remember why I made stam alternatives.. so I go back to those, and I'm back to square one.
Please give Stam sorcs and DKs something else. Wrecking blow doesn't make me smile the way it used to.
I feel like this every time now

What grinds YOUR gears?