Why does everyone hate our president so much?

I'm sorry if this question has been asked 1,000 times--I don't usually come to this section. :) Every. Single. Person. I know who is anti-Obama doesn't just dislike the man--they HATE him. Why is this? I'm just looking for some reasons why he's so disliked. Not trying to start an argument/war here...this is simply curiousity.