Never got into MMORPGs, but I am newly addicted (the last two years or so) to multiplayer FPSs, which is damn near only competitive. Being a loser in real life helps take some of the sting off of getting whupped on constantly, but the wonderful thing about, say, TF2 is that EVERYONE'S constantly dying. As long as you take someone with ya, it's a-ok. That said, I'm not going to blame anyone if that's not their bag, I just wish Yahtzee would occasionally say something about multiplayer that isn't "GAMES MUST STAND ON SINGLE PLAYER ALONE RAAAAAAHRRR." Not that I'm going to complain about this fellow who does such fine work, and entertains me weekly for free.
Oh, and I *HATE* global-only leaderboards too. BC2 won't even rank me, cuz I'm a noob and thousands of people have been playing for so long there's no room for me.