I own them all except Final Fantasy III, however I have played it over an emulator.

The worst is Final Fantasy X-2. I used to believe Final Fantasy III was the worst, but after playing X-2, I realized that no matter how bad I thought III was, this X-2 was infinitely worse.

I don't like the 100% sidequest in that game. It's not challenging to get, it's just annoying to get. You have to play all sorts of profoundly stupid minigames to get 100% and you can't skip any of the incredibly moronic dialogue. Not to mention you need to keep about 7 or 8 saves because they don't bother to show you the tenths position in your percentile.

Story is very weak, which is inexcusable (especially for a Final Fantasy). Every character in the entire game is annoying except for that one dude from Djose temple with the eyepatch. I have to listen to these terrible one liners every time I cast a damn spell. I'm even subjected to Paine's bothersome "hmph" EVERY SINGLE DAMN TIME SHE KILLS AN ENEMY in an attempt to show how "sassy" she is.

The game pretends that it's "non linear." There's a difference between non linear gameplay and linear gameplay with 90% sidequests. Not that I'd care to see either ever again.