For me, that game is Fallen Earth. It's not so much that the game burned me at any one particular time; it was a gradual decline in respect for the game after years of playing through horrible AI, broken pathing, and unfixed lag that made the game unplayable at times. The changeover to F2P didn't help anything, and when most of the core staff was eventually laid off, I lost interest.
But what always kept me going was the overwhelming good points about the game. The setting is perfect for me, the faction wheel is (was) genius, and the sense of humor is unmatched. I played Fallen Earth relentlessly since beta because it scratched so many itches for me, but the problems soon became too much to overlook.
But I just can't get her outta my mind.