That was a long time ago, admittedly, and it was a remarkably good text-based game, but the point stands: any game that requires cooperation in the shape of guilds, alliances, teams, whatever, has some sort of social pressure on people to not drop out in the middle of whatever it is you're doing. I mean, hell, why do you play MMORPGs if not to interact with people? And interacting with people means to some extent adapting to them. Obviously there are things for which you definitely should drop your WoW raid or whatever, and obviously it's bad if you spend enormous amounts of time on your game of choice because of this, but social obligations on such a game are not somehow worthless or to be ignored whenever it suits your fancy. If doing stuff together with other people is what makes the game fun, then obviously making the game not-fun for others by unexpectedly dropping out when they can't afford you to is something to be avoided if possible.