There are quite a few games that I don't like but admit are good, but if I had to pick one, it would be Final Fantasy 4. I understand it's the game that showed that RPGs could be a story-telling medium, but I just can't get into the story it has to tell. The "plot twists" are over the top and ridiculous, the characters are flat as a rock, and the setting is boring. Not only that, but even though the story has a large cast of twelve playable characters, they are switched in and out of the party at seemingly random times, causing you to lose any gear you bought for them and any levels that you grinder if they don't ever return as one of the main five party members at the end of the game. I got about half-way through the game before I took a break away from it, and still haven't finished it. I truly hope it does get better, since the random and reviewers tend to say that this is the best game in the series.
I probably should cut it some slack though. I played FF6 first, so it just seems like a step back for me since the games are somewhat similar as compared to the rest of the series.