I grew up Methodist (so no "Once saved, always saved" for me), basically "fundamentalist" though we never used the word then. I just assumed that hell existed because I was told it did. When I was in my teens I had a conversation with a young Lutheran pastor whose church nearby mine socialized and celebrated holidays with us. I can't remember how the subject came up, but he said that he wasn't sure about hell at all. I was flabbergasted.

Partly out of concern for his heresy and partly out of pure argumentativeness, I decided to collect all the passages that talked about hell. I'd show him and ask--or demand--that he explain them away. I spent a few hours over a few days looking up passage after passage, and I realized there wasn't much there. I wasn't sure how the church had come to such certainty about something so vaguely presented in its authoritative text. I never confronted that young pastor, but I sure confronted my own sense of certainty.

In retrospect, that was a turning point for me, though I didn't realize it at the time.