Why bicker?

I read with great amusement at the bickering that goes on with people of different religious beliefs. What difference does it make in what or who someone believes? Everyone is entitled to their own opinion, but why try to force it down someoneelses throat?
I have Christian, Muslim, Buddists & Atheists who are friends I even have some who believe that one day the mother ship is comming back to get them but not one of us try to force our beliefs onto each other.
At the moment religion is the flavour of the day what is next; what we eat, how we dress what area we stay in?
Come on people lets respect each other for who we are not what people want us to be