Interesting topic. Let's see... why do I resent Ash... or Satoshi, if you prefer. My reasons may be pretty bias... but that's how I roll.
First off... he's too much of a goody-goody person. Surely he could back off and let people deal with their own problems sometimes... The one time I liked his personality was in this episode in the Battle Pyramid or something... when that evil king guy possesses him. And that wasn't even his personality.
Well, this IS a children's show. Of course the main character would be like that.
And I guess the fact that he always wins, in the end, upsets me. I wish he'd lose more... and that Team Rocket would actually be able to get away with a trap.
Recently, Ash has been losing to every random trainer he meets. It's not even funny. And TR is comic relief. They never win.
Also the part where his Pikachu always beats everything. Sure,it's a TV show that's very different from the game, but... yeah. Pikachu beating, oh, say, a Dragonite with... Thunder? I think not. It may have a base damage of 120, but... haha. No.
Again, Pikachu has lost to EVERYTHING recently. It even tied with a ****ing Elekid!
Lastly, I believe I find him annoying mainly because... I naturally like villains or darker characters (J, Paul, Zero, etc) better than the heroes. Weird, I know...
Well, that's how you are. But J is the worst character ever. That personality is even more stereotypical then Ash's. I'd like to see her battle Ash with his BF team. It would be as funny as hell.
J: Oh, you're that weakling from before.
(J is owned in under 20 seconds and arrested)
Well, that's what I think. If people like him, sure, I don't care. As long as they don't talk about how 'awesome' he is, yeah. So that's my Satoshi Hater explanation.