A lot of things. Mostly the idea of this “Loving God” of the New Testament. In fact the entire NT seemed like a snake oil salesman’s pitch to me; except for the Book of Revelation.
I’m saying it was the last straw that broke the proverbial camel’s back. To see the most good, decent and truly faithful (to family, country and God) man I’ve ever met reduced to a whisp of his former self and for his God to do nothing for him truly stripped me of whatever faith I had left.
I have come to believe in a force that I refer to as “The Divine”. This is a force, not a sentient being. The purpose of this force is to test human Souls to determine if they are worthy to move in to a better existence or to be sentenced to eternal misery. It does this by placing tests, obstacles and impairments in our way to see if we will do what is Right when doing Wrobg would be easier or more immediately beneficial to us. At the end of our lives our souls are judged and with allowed to move on, sentences to eternal torment or sent back here to try again.