I was raised as a Southern Baptist. That's the sect that split with the other Baptists in the 1800's because they thought the bible justified slavery while the 'northern' Baptists didn't.
A defining theme of my religious upbringing was fear. I was scared to death of hell and the imaginary consequences of the disbelief I secretly harbored. As a kindergartener in a Baptist school, I remember picking a fight with our teacher over how the universe came into existence. Discovery Channel was a new thing and there had been some show on that explained the big bang. Not that I understood the concept entirely, but I accepted it as fact more readily than the 'let there be light' version.
I shared my thoughts on the matter with the teacher and argued with her to the point that I was separated from the rest of the class that day and was nearly permanently removed from the kindergarten. I remember the teacher wispering to her assistant that I was on a
path to hell at such a young age.
Similarly, I heard the resurrection story and it just never made sense. I tried so hard to believe it; I wanted to desperately because I wished to avoid hell. I had some pretty strong cognitive disonance going on for most of my teen years as I struggled with my doubts on the matter. I was baptized not really because I believed in my heart of hearts, but 'just in case'.
Fear dominated my mind and my indecision. I knew it was nonsense but an eternity of hell is nothing trivial to risk. It was when I finally had the thought 'If I just don't believe for a day, if I just deny the Lord's existence for a day and nothing happens, maybe, just maybe it
is a fairytale.' I lived through that day and never looked back. My life has actually been much happier since then for other reasons, but this tends to reinforce my disbelief.
Fear of hell kept chains on my mind and did far more damage to it than many other horrible things I've endured. Fear chained my wife to faith as well. I remember how upset she was when I pointed out how Christianity started as a cult that was seen as outlandish as Scientology and that someday, just maybe Scientology would replace it. She had the same doubts and fears as myself and my example unsettled her.
I took her to see Religulous and we both thought it would upset her. But something in the absurdity of the things in the movie broke the chains for her. We've lived as happy little athiests ever since.
In conclusion, I believe that the defining difference between a religious and an athiest upbringing is the lack of fear the latter enjoys.
BTW - I always tell my athiest club buddies that I'm a devout athiest and that I
know there is no god with certainty. I do this not because I actually do know this with certainty, but because the kind of silly semantic arguments they love to get in over essentially identical words and concepts are just too easy to troll. I see a lot of this in this thread
