I'll take the easy route and go with my least favorite game of all time, The World Ends with You for the DS. Every negative stereotype associated with J-RPGs applies to it, from a cast of bitchy, unlikeable characters to a convoluted, pretentious, nonsensical plot to a gimmicky and easily breakable battle system. As far as a character I hate goes, I'll just take that game's protagonist, Neku Sakuraba. He has no redeeming qualities of any kind; he is misanthropic for no reason other than he thinks it's cool, his fashion sense is atrocious(even though he works very hard on it), and he constantly insists that he cares about nothing at all(untrue) before he makes a complete 180 halfway through the game and turns into an obnoxious, saccharine wiener. The only character I can think of who appeals to me less is Sonic the Hedgehog, or perhaps Mega Man.