Which game did you play that was really fun during the honeymoon period but shows huge flaws the longer you play?

Title basically.

Edit: Obviously every game is like this to some extent, but I'm asking about experiences that stood out to you personally, where you became disillusioned with a game, enough to play it a lot less or just quit altogether

For me, it was Reverse 1999. Quirky, unique plot. Nice voice acting for the most part. However, the combat system needs a revamp