As a child and in a religious college i studied the bible and came to know it fairly well. But i was already leaning away from religion in my early twenties. Then i took anthropology at a community college. Suddenly i couldn't just accept that both science and the bible were vague enough to not contradict. I made a conscious choice that believing one meant leaving the other.

I'm sure there's plenty of religious people who don't know enough about their religion to know it can't work.