OP: Sorry you've had such a hard time with runs with aggressive DPS. I main heal myself, so I've seen the abuse. However, on the flipside, when I go in as a DD, I at least try to ask politely if we can do a full clear. It doesn't hurt to ask. Think of it this way, though: a DPSer has just had to wait 30+ minutes to even get a chance to enter a dungeon. So literally, every ounce of extra XP they can squeeze out of the dungeon offsets the hellacious wait they've had to face. I'm not saying you weren't taking that into consideration, just please do keep that in mind. I was in two dungeon runs today where the tank completely ignored my (polite) requests to do full clears. I didn't push the issue, but it was incredibly frustrating, as we easily left 40,000 or more XP on the table, which I had to go grind on my own on hunting logs just to level up, because I damn well wasn't going to wait another half hour to queue up. It happens, just... ugh.

I've played every role and have leveled every job in the game to 50 except DRG and MNK (those are next!), so I totally understand both your frustration and theirs. Nobody likes pushy people in general. But you're right... people being jerks is the number one reason why tanks (and healers!) are so rare.

Anyways, hope you have greater success and fewer encounters with jerks. Good hunting!