If you are referring to what I think you are then this bugs me too. Also, there is an open area right next to us, but you're stopping in an enclosed space and these mobs have hard hitting AOE's or directionals that everyone is being smacked about by. Then they are surprised when the group wipes.
Another thing that bugs me are tanks who dont commit to their pull, they stop and start constantly, moving off again with a half damaged back of mobs. They do realise that a lot of DPS jobs have windows to use their bread and butter skills? Ive seen wipes happen because the tank couldnt commit to their pull and the DPS were down. Obviously thats only really a risk with packs who need to be taken down quickly, but still.