I have never been a fan for a variety of reason.
1) You already bought the game and now you have to continue to pay for it: I know this isn't entirely true now with many MMOs and other only focused games having free to play options, but growing up you still had to buy the game full price then throw down $10 to $25 a month + the cost of internet to continue playing. I always felt this to be a huge ripoff and I still do mostly.
2) I don't like online multiplayer: I don't really like interacting with people normally, but interacting with others via a game is arguably worse. Probably because each player gets to hide behind a character they're playing, the worst parts of who they are that they keep hidden in real life come out for all to experience. Because of this I find dealing with people's mental illness, bigotry, egos, and insecurities even more annoying while playing a game than I do in real life.