FATEs - most boring content there is to me.

In 95% of all FATEs you dont get to play your class properly - either because the FATE is over way to soon because its totally overcrowded or because you play as anything but a tank (so casts get interrupted, positionals are out of the question, healing doesnt really matter... ranged might get away with kiting) or because stuff dies so fast that you really question wether or not its worth to apply your dots... I could go on.
There are a few FATEs that have neat little lore-bits or some funny description texts and I really enjoyed the long FATE-line in the stepps, but besides that they also often include to much downtime, where you can do nothing but sit around and wait for the next FATE to spawn...