I hate Self-Entitled Tanks
This is coming from someone who has a long history of tanking both in FFXIV and many other MMOs, but I personally hate tanks who feel the need to punish the whole party because their job as a tank isn't all wrapped up in a nice little bow. I'm talking about the type of person who will kick another player for doing aoe instead of attacking only his target or who won't pick up adds that get accidentally pulled (which is usually from the tank's bad positioning of the enemies in the first place). The only reason why Tanks specifically feel so entitled in this game are because of their short wait times, meaning that they don't care if the Duty fails or you kick them because they don't have to wait for anything.
Just recently I had an ordeal happen in Aetherochemical Research Facility where the tank would keep very little aoe aggro and tried to pull very few enemies. During the first pull, the other dps in our party was confused as to why the tank didn't continue and accidentally ran into the wall of 3 mechs that spawn. Not only did this tank refuse to take these adds from the dps, but he didn't even re-aggro 2 of the initial enemies when the healer stole aggro from him. This event essentially repeated itself until we got to Regula Van Hydrus, at which point he went eternally afk, making it so that we 3-manned the boss while waiting for the 15 min initial wait to lift so we could kick him.
Of course, there's also the type of tank who doesn't really know how to, but when you try to help them in earnest, they spit in your face. I remember a problem I had with a player some time ago where he was playing a Gladiator (not a Paladin) in Dzemael Darkhold and he had on Disciple of the Land gear. While the first part of the dungeon and even the first boss is completely doable with those shortcomings, it became increasingly evident that he didn't even use flash to hold aoe aggro. Upon informing him about the Job quests and telling him that using flash will help him hold aggro, he started cursing at me and telling me that I don't know what I'm talking about. He then proceeded to do absolutely nothing (not that him auto-attacking was reallying doing anything) and follow us around presumably trying to get me kicked. The party as a whole was wiser than that and we eventually kicked him, but unfortunately after doing so, he was able to instantly re-join 3 times, essentially ending our chances of finding a legitimate tank that could complete the Duty.
I'm all for teaching new players how to play or trying to help players who are struggling with their roles, but when in a Duty you must participate, and intentionally failing to do so in order to cause others grief is a reportable offense.