Lies! Rock Lee is unhateable. :O
lol!
Initially, Rock Lee was one of my least favourite characters in Naruto. I think that is the way it is for most people who watch it. I've watched it with several others who were watching it for the first time, and they're reactions were all pretty much the same. "....omgwtf??? o.o;" That was kind of my reaction, too. ^^; But then, I think as you see him more in the series, you see his character more for his personality rather than his strange appearance. The main turning point for me, I think, was his fight with Gaara. (And it's the same for the others I watched it with.) I think that's the first time that you actually see how strong and determined of a character he is. He's still not one of my favourite characters (only because I have so many other favourite characters), but I really do find him to be a very endearing character. His determination, kindness, and politeness is admirable, and his loyalty to Sakura is very sweet... ^^
As for the anime/manga character(s) I dislike... I really can't think of many. The only one that I really dislike is Shiori from Shoujo Kakumei Utena. For some reason, I just find her to be absolutely disgusting. I think it's the fact that she does not mind how much she hurts people as long as she can temporarily feel good about herself. I really have a problem with people who have to put other people down in order to feel better about themselves. And Juri is one of my favourite characters in Utena, so it saddened me that she allowed Shiori to have such a negative impact on her. I really can't understand at all why, even after everything Shiori did, Juri still loved her. And I really thought her and Ruka would have been good together, too. Ah, Utena... that series could really be depressing, at times. =/