Any challenge or super boss from FF X and X-2, especially the ones that break the rules of the game. Whats that its petrify overrides my status protection, and it breaks the damage limit 10 times over in 3 turns... what a load of bull. I've beaten every other games super bosses, some were a challenge and required advanced planing and strategy, others were way to easy, X and X-2 were just unfair. What kills me the most about these bosses, is that we in the US didn't get the international versions. If I could fight Penance I would not even care, I'd bust my ass to beat it, instead I get to fight a whole lot of challenge bosses in what feels like a prototype for the glorious international version. I mean think about it, in X-2 international I can replace Paine with Tidus, hell yeah why couldn't I play that version.