Just wait till you DF the same dungeons as a DPS class, after loooong queue... and get a derp tank. Who don't understand your words. Who don't flash at all. Who will *walk* all the time in wrong directions. Mark targets? Pull cubes on platforms? Grab adds? Stun AoE? Haha. And then you ragequit after wiping repeatedly, getting 30 min DF penalty on top of DPS queue time. Sure, tell us more about "not tank-DF ever".
<- prefer doing roulette as a PLD, at least this way one can get some control of the situation.