I notice that other players frequently attack the mob I am already fighting. I don't mean they pull it at the same time or whatever--I mean that while I have been fighting, they'll come finish off the mob.
It doesn't really bother me. I just can't figure out the motive. I'm sure it isn't generosity and team spirit. Do you get some of the xp or a chance at the loot? Most games I've played, once a player hits a mob, only that player and group members can loot. Is that not true in ESO?