Just wait until you get to the higher level dungeons where you raise someone and then the boss decides to throw an aoe right where the person respawned.. SO MANY TIMES D: All that MP wasted...

On topic: Just make sure you have the correct gear and that you are casting Stoneskin before pulls at bosses and if you can before each fight for the tank. Also sometimes, it isn't your fault.. Some tanks don't have the equipment they need.