Open Question of Faith

I want to pose an open question on faith to world at large.

What do you believe and why?
I know that is too general. What I am looking for is an understanding of what makes people tick. What is convincing and why? So, if you are atheist, agnostic, christian, muslim, hindu, et cetera, why do you believe what you do?

Note: Because X book says so does not cut it.