So i play both horde and alliance, and from my personal experiences alliance players are much more hostile, max geared players go camp northend leveling zones or even lower level zones, like why.. ok fine, kill me once but why just keep waiting for my respawn and keep camping me, are you that fat of a loser ? like holy ****kkkk, like i said this happens waaayy more when im leveling a horde character than when i play alliance.. WAY too many fat losers on alliance i guess.
My rule of thumb is this: I leave them alone as long as they leave me/my lowbies alone. The moment I get ganked, I will kill all Horde in sight for the next 10 minutes regardless of level/gear. This has always worked well for me. And yes, I will kill the same guy over and over if he is dumb enough to return.