Every MMO has repeated content. It’s part of the very nature of the games. Maybe you’re repeatedly doing a dungeon, or repeatedly grinding enemies, or repeatedly getting back all of your stuff after someone teleported in and hit you with fireballs until you died before stealing your stuff for kicks. The point is that there is repeated content to deal with, and if you are playing an MMO at some point you will be engaging with it. The question, then, is what sort of repeated content you find particularly obnoxious.
For me, slowly formed groups for repeated content kill a lot of the enjoyment, and repeated PvP matches tend to drag a bit. But for some players, grinding enemies is repetitive in the worst way and outright deplorable. Others really dislike repeated dungeon runs regardless of whether or not you can queue up for them. The list is as long as the list of repeated content types, and so we ask: What sort of repeated content do you find least fun in an MMO?