I tend to do this too, but it's mostly because there is a finite amount of things to do in a game, and if the game is fun enough to play, it's almost certainly fun enough that I want to do more than there is to do. If there were more randomly generated content I'd probably focus on the things that suit my character rather than trying to build a character that suits the game. Also, replayability isn't very high in games where most things are already custom designed rather than randomized, because that would mean that the story is also set to a large degree, so I would usually not want to replay the game just to explore the story from a slightly different angle. Half the fun in an RPG, be it computer or PnP is the feeling of
possibilities, and that feeling is seriously hurt by already knowing the story in advance. But this is where a CRPG without obvious stats would help, because with no visible stats it ought to increase the feeling that certain things are possible, even though the game might actually be ignoring those things. As long as the player doesn't find out, there's always a chance that there really is a secret cow level.