What exactly are the Sunnis, Shi'ites and Kurds fighting about?

Iraq is made up of Majority Shi'ites and some Sunnis and Kurds in the north. Saddam was a Sunni leader in a majority population of Shi'ites. Shi'ites hate sunnis and sunnis hate Shi'ites. Shi'ites finally gained political power which they were surpressed for decadeds. Kurds are in the North and its peaceful up there and they are doing there thing. Sunni's are not willing to give up something they once had which is currently taken over by Shi'ites. Its really a religious war with a lot of hate and rage towards each other. The Shi'ites and sunnis are fighting for Baghdad right now, they both dont want to share it. Iraq has always been a battle ground for thousands of years and it will never stop. They are cowards and the stupidest arabs alive. They can't live with out killing, thats the way they are. They need a ruthless leader to control these people, they don't need democracy.