Oh man, I've played a shit load of MMO's, though honestly 99% of them I really enjoyed my time in them, even if some of them I never bothered subbing past the initial month. True, they didnt have enough to keep me subbing, but at the very least, the first few weeks were pretty fun. My worst ever experience was probably an oldy, and it was Anarchy Online. If my memory serves me correctly, it was sorta being hyped due to being one of the first new MMO's that came out after the big 3 (UO, AC, EQ), and it had the whole Sci-Fi thing going for it, in a world of fantasy MMOs. I remember I was fairly hyped, and the day came and I installed and played it...and I felt so betrayed. I didnt have much disposable cash back in the day, so buying this game and then having it shit the bed was a big deal.
I remember that was back in the days when you didnt get any real news on MMOs, and had to rely on fansites and random forum posts as they slowly dripped out info. When e3 was actually huge for MMO's, as they would hype that date up so much and then have a massive info dump when it finally arrived. All those little fansites like stratics/vault/lum the mad, dr twister etc. Man, everyone took it so seriously back then. If you were a hardcore MMO fan back then, you were a fan indeed. Love how so many fanboys would go on to eventually get hired by companies as PR guys and stuff. Good times.