I believe in God. My god is so loving, grace filled and merciful, he wouldn't condemn people for being atheistic or agnostic or not accepting Jesus or what have you. Who would want to love a God who would condemn anyone with good in him/her? I wouldn't. I figure God understands that people have good reasons for their lack of belief or being unsure of his existence or interest in humankind. He knows there is so much confusing religious crap slung around and he knows of all the evil committed in God, Jesus, Allah and whatever's names.
Proof to me? When I see a graceful ballet dancer dancing. I took ballet classes for several years. I know how hard it is to dance that gracefully and do the things they make look effortless. When I see a runner or a figure skater or the amazing things men and women create, I know there's a God.
The one thing that kept me from ever being an atheist is the love we all feel for our families and friends and the way we grieve when one of them dies. I also can't see how a talent like that of Jimi Hendrix or Vincent Van Gogh just somehow happens and then is gone forever when they stop breathing.
If a person is comfortable with non belief in God or being an agnostic, so be it. I believe in the inherent good in most people. And people who seem to do mostly evil? Who's to say there isn't some genetic problem or mental illness that is only known to God?