I kind of OD'd on MMO's back in the days when Everquest was king. I played with some RL friends and, when they got sucked into an uber-guild, so did I. Pretty soon it was a second job and about as fun. Still, being elite was addictive. Eventually, I had to choose between virtual success and real-world success. There just wasn't enough time for both!
The funny thing is, this experience completely turned me off of multiplayer games, MMO or otherwise. I used to enjoy logging into FPS servers and wasn't half bad at several popular games. There was no time for them when I played MMO's, and I've never gotten back into them since. Since I know people who used to work at Bioware, I've long made a point of playing every single one of their games. That ended when they made a MMO. I briefly played Mass Effect 3's cooperative multiplayer, but I couldn't stand even that! There is absolutely nothing that breaks immersion and destroys your enjoyment of a game universe like listening to teenagers talking smack.
Yeah, I'm a geezer now I suppose. Damn kids, get off my Quake server!