bosses tend to lose aggro, usually when they are casting those red area skills.
and, usually they would change their target to your most damaging DPS, and (some) put the red carpet exactly below their feet.
at this time, use roar to regain control and save your DPS's face
actually this is pretty good IMO
if the boss never loses aggro, and keep attacking you like a raging bull, and your DPS team can spank him non stop without worrying anything, this game wouldn't be so interesting.
love it when random dumb ppl died because they didn't avoid the red carpet, wtfraged, and start blaming the bard and tank.
making them more dumb-looking.