These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alt-itis: Acknowledged and encouraged with the level 30 Daevanion armor sets. Each piece is received through a simple quest at the set's level... and each character can only get one piece. The armor skin is also exclusive to the set.
It's Easy, so It Sucks: Taloc's Hollow solo instance, accessible to level 51 or higher characters. You are practically impossible to die as you are given a super buff that gives you 100,000 HP, a 5,000 damage AOE attack and a 7,000 damage single-target attack (10 second shared cooldown), and a super-powerful defensive skill - while filled with fake "Elite Mook s" having stats roughly comparable to 1-2 star non-elite ones.
Scrappy Mechanic: Aethertapping. Aether is required for all Item Crafting, but the nodes are only found high in the air. Combine with your measly one minute of flight time requiring two minutes to recharge, and you're going to spend a lot of time tabbed out of the game waiting to fly again.
You can use Wind Serums to recover your flight time. There are also equipment that increases your maximum flight time, although they do not speed up your flight time regeneration.