Cant leave any loot, doesnt matter what it is.
During raid encounters I tend to move/fidget a lot. I don't know why but I hate just standing still. I remember frustrating some fellow raid members in some encounters, like the first boss in H MSV when you got that link with another player and had to group up. I'm melee so if I got a ranged person I'd always be fidgeting and would annoy my fellow linked person. Obviously if I have to absolutely stand still or it's a raid wipe I manage(e.g. that one Shade of Aran ability in Kara, or that one boss in Heart of Fear with the wind bomb thingies)but otherwise I'm just a constant fidgeter. It's not the worst habit I guess since it keeps me on my toes and am able to dodge things faster/better being that I'm always on the move.
Always playing the class that is overpowered at 1v1 pvp. This...habit started a long time ago in TBC when I was camped in Quel Danas by some asshole and there was not a damn thing I could do to fight back because he was playing a feral druid and those were sick in TBC when they could switch to bear and do as much damage as in cat while tanking you.
I swore I will never allow this to happen again.
As a warlock, I get extremely frustrated when people ask me for summons or healthstones. Not just a little annoyed, but very angry. Like I know it's a part of my class, but I almost always do them without being asked anyway. The fact that people don't notice when I do it annoys me, so I had to resort to making a yell macro when I drop healthstones. So frustrating.
It especially grinds my gears when I put down a summoning portal and everyone stands there and doesn't click on it.
<3 Kuragalolz for the signature and avatar
I have 90s of every class, and while hotkeys are similar, rotations are different. Like every class of mine has mobility spells like sprint, blink, and roll mapped to the middle mouse. 1-6 is the regular rotation, with ctrl + 1-6 as cooldowns/aoe rotation. I have a system, but like someone else said, I'll be playing my warrior and have a massive brainfart and start using the muscle memory of my rogue's rotation. If I haven't played an alt in awhile, I almost have to relearn how to play. I'm currently on a break from live and playing beta, and I'm screwing up rotations.
On the beta, I've developed a habit of wasting my Counter Shot constantly, because I put it in slot 3 on my action bar which used to be occupied by Serpent Sting before the ability pruning. I'm too used to firing Serpent Sting that I can't help but press 3 too often. Same habit applies to slot 5, which used to hold Hunter's Mark but now holds Tranquilizing Shot. :P
I really need to re-organise my action bars.....
Running around in circles mindlessly while talking in vent after a raid. I waste sooo much time doing this when I could be joining LFRs or doing daily grinds or something while unwinding. But I end up getting caught in my circles around shrine and don't go out and do anything with that time.