It is al PP fault! Trust me on this XP
If you don't, read below.
You need PP's to advance, you gain them after you kill a mob, so it is important to kill a mob. Because of that, once you hurt a mob, you own it, and everybody around are frustrated because of both IC ad OOC reasons.
What if there is no PP?
The fact who kill the mob doesn't matter at all, so there is no reason why someone would have to own a mob, after that person hurt it. Everybody can attack the same mob at the same time.
Now someone will screem: but what about the loot??
It is simple, the loot rights are for this person who inflicted most damage from all to the mob. If it is a group, their damage is sumed.
Believe me, we avoid loads of problems and complaining this way ( this post would get 3 times bigger if i started to point out, most are in this thread).