Even after ~1500d played, I'll have to answer with a definite No! For me the game is:
1) Playing with friends/WoW-buddies as they add an interesting social aspect to the game, plus pretty much any dungeon run feels a little bit different than last time (raid runs much less so). PUGs can range from excellent to horrible, but so is pretty much every random person you meet up with IRL.
2) Farming rare things (appearances, mounts, toys). These things having a random chance to drop, therefore taking time, makes total sense in an MMO as time investment is introduced as a variable. Again this becomes entirely pointless when other people aren't there to compare collections with. In addition, farming RNG things never made sense to me in single player games either.