First of all is the most important and annnoying... The interact bug... Right click doesn't work, npc's cant be clicked on, nor can players, nor can quest objects, or anything that you would need to right click on, can bug out.
Biggest problem with this, RBGS we were in Gilneas, and I went for a ninja cap on mine's... killed the person there, and after looted their corpse, I hover my mouse over the flag to cap and.. GUESS WHAT nope, can't click, no way to fix it unless I log out of the game and back in which I cannot do in rbgs...

Second, is the phasing bug.
Many many many many people, are being phased when they shouldn't be, so quest objects, npc's, and other things aren't working, for instance the quest "Battle helm of The Thunder King" isn't working because of this, there's at least 20 quests now in the last week that I haven't been able to do or complete that some have because they are not being phased.