If there's a game that is in some aspects (like story, playability, structure, difficulty) really great and in others absolutely awful and there's another game that is mediocre in everything, nothing special but neither terribly annoying, which game would you rather play?
I just finished one of the latter type and came to conclusion that it's much more enjoyable to play something that doesn't have major faults, even if it doesn't have anything particularly good either.
But... years later I won't remember much about the all mediocre game, while I do fondly think of the games that had something great. And thus I'm more likely to replay the game I enjoyed less. (Fortunately that hardly ever happens because I have enough actually overall good games to replay - not to mention that I buy new games faster than I can play.)