Hated
Ash from Pokemon - why does our protagonist have to be the most moronic person on the face of the planet? I even like Pokemon, but I hate Ash. Oh, and Todd, too. Stupid.
Foghorn Leghorn - annoying and stars in the exact same cartoon about 20 times. Granted, the same thing can be said about most Looney Toons characters. While I’m at it, I’ll throw in that stupid female chicken with the bonnet and the glasses and that little chick with the huge glasses that was really smart, too. A pox upon them!
Goku from Dragonball Z - for pretty much the same reasons as Ash. Aside from the fact that he’s a moron, he always, always has to be the one that saves the day. And if it’s a rare occasion when he’s not saving the day, it’s because he sacrificed himself for the greater good (i.e. is Jesus). Oh, and he’s always late for the battle. Just late enough so that I can see characters I actually like get their asses kicked. Thanks, Goku. Fucker.
Homer Simpsons in new episodes of the Simpsons - I can’t think of the exact breaking off point, but at some point Homer went from a dense but loveable individual to a complete asshole who doesn’t care about anything except his crazy schemes. Really annoying because I used to like him so much. On that note…
Loved
Classic Homer Simpsons - He wasn’t very smart, no, but he was one of the most easily likeable characters on television for a lot of years. Also responsible for some of the best lines ever uttered on television.
Eric Cartman - absolutely wonderful character. A complete and utter asshole, but amazingly fun to watch. And if you piss him off he’ll feed you your parents. I mean, really.
Sid the Sloth - I would never have thought of this without the OP, but it’s so true. Great character.
Scar from the Lion King - my favorite Disney villain. “You see, I? Well I shall never be king. And you, you will never see the light of another day.”
Rocko from Rocko’s Modern Life - How can anyone not like Rocko? Honorable mentions to Heffer and Philbert.