Proof for God?

One thing I have always wondered about creationists is their need to prove their Bible is 'true' and their god is 'real'. I thought the idea of religion was to take God on faith. If you have faith in God why do you need to prove he exists to non-believers? Or am I missing something?

I am not asking anyone to accept evolution as true... I just don't understand why creationists I talk to feel somehow obligated to force their truths down my throat. Why can't they just accept that I don't believe what they believe about God and the Bible and leave it alone. Evolution on the other hand isn't, to borrow from the Indiana Jones movies, the quest for truth it is the Quest for facts...And evolution is an observable fact...It has been observed in fruit flies whose new generations come along every few days. The only real questions about evolution is exactly how it happens and on what scale.