If your a healer speak up and let them know how many sets you can take. Also some tanks are just lack common sense. I do have healing experience, tank to get daily done, yet prefer to DPS. Your right some tanks lack common sense and communication. What sad is if you do keep up they can't keep hate properly and blame the healer.

As a tank ask if its ok, doesn't take but a few seconds.

If a healer speak up.

As a DPS be well geared or let them know your a bit under gear so do a DPS gauge pull first.