FFXI. Perhaps you think it doesn't count, but it's Final Fantasy and it's smurfing hard, so I say it counts. The game became much easier around the time of Abyssea, but before that, it was soul-crushingly hard. No quest UI, endless grinding (seriously, endless), annoying party requirements, lag (looking at you, dynamis), endgame bosses that don't give a flying smurf about how many hours it took you to farm the items necessary to make them appear or whether you have a real life or not, and insane endgame gear (relics weapons, etc.) collection requirements. And all of that was soooooo worth it.