If we're talking about sheer forgetability, I think we should all be honest and agree that FF6 takes that cake. I mean, does anybody even remember the story? It's about on par with Half-Life 1.
Part 1: "Hey, it's Terra in a robot"
Part 2: ?????????????
Part 3: "OH SHIT FLYING ISLAND!"
Part 4: "Ha, Kefka's dead."
For reference, Half Life 1 went:
Part 1: "Oh great, I'm going to work."
Part 2: ???????????????????
Part 3: Dude with the suit does something?