I left religion, ironically, because of Hebrew School. I was a younster and sent to Hebrew School, where an exceedingly kind older women, patiently taught us Jewish history.
She had a blue tattoo of a number on her arm. When I learned about the Holocaust, and the origins of the tattoo, I couldn't excuse a God that would allow such a terrible thing to happen to such a kindly woman.
I didn't tell anyone what I thought, or felt, or decided. But that was the end of me and religion.