Wow, so you pretty much put it all on the tank? If this is the case, tanks are pretty justified in acting like assholes at times.
At times. Tanks shoulder a lot of responsibility and need to have as high a standard of awareness as the healer, while also doing as much damage to the mobs as they can to hold aggro.
Here's a good write-up on the role. Even if you ignore the WoW-specific stuff, it would be a great read for someone starting out in FFXIV: http://www.icy-veins.com/tanking-guide-wow
I'll copy and paste the most important thing:
icyveins said:•A great tank always has top aggro on all targets that they are assigned to tank, and not on any other targets.
•A great tank has excellent reaction time in picking up new mobs, before these mobs attack other raid members.
•A great tank has excellent reaction time on taunting back targets that they lose aggro of (which happens to everyone at one time or another).
•A great tank is intimately familiar with all the fight mechanics, and because of this, knows when and where to move, and when and how to use their defensive (and sometimes offensive) cooldowns.
•A great tank understands the various positional requirements of (especially melee) DPS players, and does a good job at minimising their movement and downtime.
•A great tank has the qualities of a leader, and is not shy to step up and take control of the group.