Okay, for amazingly cheap final bosses, giving them an instakill attack which they use on your party leader instantly losing you the battle takes the cake. It's bad enough that they periodically drop your hit points through the floor regardless of defenses (UGH, so much... healing...) but winning in such an incredibly cheap way just makes me want to say FUCK YOU FINAL FANTASY XIII! FUCK YOU FOREVER!
At least the second through fifth times they were quick about it and randomly instakilled me right away. The first time they let me get them down to about 30% before randomly instakilling the party leader. Because it's SO much fun to be fifteen minutes into a fight when you lose in the CHEAPEST FUCKING WAY EVER IMAGINED IN THE HISTORY OF THE FUCKING WORLD.