I was a victim of cyber bullying in an earlier life, not that I care much if people try to be smart these days but back then it had a large impact on me, I quit roughly during mid 3.3 after having been around since 1.4, missed the entirety of the cata pre-event and rejoined roughly 2 months into cataclysm, found the game boring after 1 month even if most of the people I had disliking to had gone, and left again until 5.2's ending just as 5.3 was about to launch.
I confess, if I leave WoW again I don't think I will return, it will mostly be out of a culmination of things, but most of all, long term decay, my last break was nearly 3 years long, the next one is likely permanent.
Fortunately, most of the people I know now are good folks and ironically while the toxic elitism of WOTLK passed on the community attitude while seemingly more isolated has over-all improved. So on a bullying side, I don't have any issue with WoW's community these days.
The game itself though? Its slowly decaying, as is my interest in it, I dunno, ill stick it out till next expansion and if that doesn't hold me I think I'm done.