I always felt this way about Final Fantasy X. I've always found IV,V,VII,VIII, and XII to be great games. With III,XI,I, and XIII being pretty decent, but X and II are downright unplayable. However X gets a lot of love, and I've never understood it. Regardless, I've never played through VI. I just picked it up on Super Famicom recently and I'll actually be playing through it for the first time this year. I originally had it on PSX but couldn't get into it then...perhaps now on the actual Super Famicom, I'll find it more playable.
Like a recent theory I had about X, that I mentioned on here before. Much like my love of VIII, and V. I think you just had to be there. I think X was just a lot of people's first RPG, or First or Second Final Fantasy game, or they just played it at a time when the story actually meant something to them. To an 18 year old such as myself at the time, all I was seeing was a whiny kid with daddy issues and horrible fashion sense. Whereas VIII struck all the right chords with me at the time (along with VII). However, I've been with the series since the beginning missing out only on VI for some bizarre reason. Maybe I'm just too old and unhip to ever get into X. Maybe you just had to be there at the height of the 16-bit era to really GET VI.