Classic WoW is fun as fuck and I'm really interested to see if they're going to re-release TBC or new classic content after it's run its course. I got to 60 and did MC a couple times before accepting that I absolutely do not have the free time or self control to be playing WoW right now.
I liked ESO better before they added level scaling to dungeons and made daily dungeon rewards. Really ruined lower level dungeon runs for me. I really love the PVP, though.
Guild Wars 2 is a lot of fun, but I dislike the lack of traditional healers because that's my favorite role to play in PVP.
I can't play MMOs because it's basically an addiction when I do.