Ash Ketchum himself. I don't hate him and I probably never will but I really don't like him anymore. Since DP started into Best Wishes I find myself liking him less and less as time goes on. Just repeats the same thing over and over again. Half the stuff he learns he already learned in a previous saga. His childish attitude after all these years has gotten stale and not even reverting back to his Kanto stage in BW has helped me to like him again. I guess I don't mind him not winning a league to much even though I think he's long overdue, but in my opinion that really holds the secondary character back. I think the writers chickened out at the Sinnoh GF because they knew Ash wasn't going to win the league so they made his sidekick lose just to be fair, not that I had a problem with that, but seriously why make it to the finals just to lose and never be seen again? Ash's Pokemon are all nice but they just get personalities of his past Pokemon. I mean Treecko, Buizel, and Snivy all have the same feel to them. Oshawott is just a much better handled Piplup that's not so in your face, And I won't mention regional birds. I also really dislike the idea that Ash is the only special person in the world. Nobody else can see legendary Pokemon or save a legendary Pokemon but him (Movie 9) so there we are.
RIP anime version of Glovehead. Pokemon Adventures will save you.