I don't like Djokovic, because I thought it was incredibly disrespectful to the game and his opponents, when he used to retire in big matches. I lost a lot of respect for Justine Henin after she did the same, in the Australian Open final against Amelie Mauresmo.
I also used to hate his family, with their tracksuits with Nole and their over the top cheering. Honestly, they were as bad as those Aussie Fanatics! Thankfully, you don't see much of them any more.
In addition, he is petty: he can't take a joke against himself, although he loved mimicking lots of other players, and he can't stand it when he's not the crowd favourite.
But he has a very good game technically and a great work ethic. I respect the single-minded determination he's shown to become the no. 1.