It's habitual for me, generally, when fighting a boss, to turn it around. If other melee DPS classes are soft hit/expertise capped (capped when only attacking from behind), by doing this, the DPS are already in position for their maximum potential.
Additionally, Many bosses may have abilities that can be detrimental to your group if they're facing it. Turning them around is a sure fire way to make sure you don't subject your group to the bosses that have these abilities (like a cleave damage, Fiery breath, or other frontal only AoE attack).
Watch out though, some bosses also attack from the rear.. and with things that hit harder than flatulence!