Annoying quests:
Y'hagra Trophy and basically all of the other fester boss side quests:
It's too rng, it takes ages and sorcerer is discriminated the most, cause rogs and wars have class side quests which help them to get 200 side quests ap much faster.
Evidence of Forbidden Technology and basically all other quests from this questline:
nowadays getting antignome and banished sets is almost impossible, you have to find someone with these sets and ask them if they can borrow/rent you them (if they won't borrow/rent, you can forget about finishing these quests).
Mythic Dreamscape XXX:
666 asheras and these quests don't even count as a completed side quests if I remember.
Hot! Hot! Hot!:
this daily quest isn't hard, but it's pretty annoying, since you have to run same map 3 times.