Mindu from FF2, by far. He annoyed me for some reason. And Gordon, too. He was utterly useless.

Seymour from FFX probably has to be the one character out of all the Final Fantasy games that I hate the most. He is so damned annoying, with his stupid voice, and he just won't die!!!! You fight him like 20 times. And his hair! God, I hate his hair. Okay, that's enough Seymour bashing for one day.