Well, i'm just mentioning a couple of bugs that i've found in AO that have been bugging me(no pun intended).

Bug #1.
Treatment clinics.
Sometimes, after I die, I use a treatment after the res effects are gone. However, after the first one, sometimes the second one, The treatment doesn't heal me for much, or anything at all. Only way to fix it is to either camp out, or zone.

Bug #2.
Scooplets.
These little buggers do tend to beat on you fairly quick, and when you kill them, they don't give any experience points. You can loot them but you get nothing else.