...but then you did THAT!
What are some games that you were mostly enjoying until it pulled something that made you shake your head in shame. Was it a bad plot twist that left a sour taste in your mouth? A really difficult section that the game pulled out of nowhere for no good reason? An escort mission from hell? What games missed the mark of perfection for you because of that one thing.
This doesn't necessarily mean bad games, you could still love the game, just dread that one part; or maybe it was going in your top ten before this element showed up and knocked it closer to your top 25.