Well I personally didn't leave my faith because I was mad at the church or anything. It was purely from logical reasons. Its like you wake up one day, and then you have the curiousity to find out what is the moon made off. I still celebrate christmas, I think its a great holiday to give and get presents, plus it brings the family together.
Well I lost it from just asking questions. It started after studying cultures and learning about early civilizations, then I studied the origins of religions, and it grew from there. I also love astronomy, one of my passions that I had since I was in 4th grade, I have always been a huge nerd.
I had two lives all my life, a religious side, and a scientific side. I believed in creationism and evolution at the same time, but never crossed my mind to ever combined them both. So when I got to college, the obama vs mccain thing was going on. At that time I decided to actually investigate what I knew. So I looked into all political philosophies and I justtried to decide for myself which one I thought was more appropriate. I shifted from a conservative standpoint to a libertarian standpoint to a moderate stand point I have now. Shortly after, I decided to investigate faith vs science. I slowly shifted my viewpoints from theist to agnostic-theist. I believed that god 'guides' the universe, and that explained the question of free-will. Then I thought, is it possible there is no god? The answer was yes. So I shifted to a strictly agnostic stand point. So I thought god was a 50/50 chance. But after remembering that there are million of possibilities that there are diffrent kinds of gods, or there could be multiple gods, or gods of diffrent forms, then the chances were no longer 50/50, they were 1 in an infinity. So from default comes the lack of knowledge and disbelief. Same as people don't believe in unicorn. Sure there could be unicorns but highly unlikely. So there you go.