Why do you believe in god?

The way I see it, there are two types of people in the world - reasonable people, and insane people. If your a reasonable guy, you wouldn't believe something for no reason and with no evidence - so why believe in a text that has been transcribed, copied and edited over so many thousands of years (like a big ******* game of Chinese whispers)? Especially when the mountains of evidence for evolution contradict it so flatly? Despite this, we still have parents paying thousands for private religious education, we still have religious fanatics knocking on our doors trying to convert us, and priests brain-washing their congregation! Why?!?