As a tank I often find myself FORCED to hurry to the next monster, because I know that the DPS will try to get it before me. And since the puller always starts the fight with maxed enmity pool (those little pools next to your name in the party list, for reference), the other party members will be forced to start the fight with a 0 enmity pool. It's very stressful and sometimes difficult to slowly climb my way up to max enmity to get the monster off the puller, who almost never even tries to help his enmity go down and just keeps shooting arrows or spells at the target in a "I'll kill it before it kills me" spree.