My mother was raised in an excruciatingly catholic family, she understood that that was not the way to go and instead brought me and my brother to an Episcopalian church every sunday for most of my childhood. I always tried to believe what I was told, but always had so many questions that nobody would answer. Eventually I started getting in trouble in sunday school for asking too many questions about what they were preaching. I continued to go until every sunday until I turned 19, being actively invlolved in the church, but gradually losing any faith in the diety.
Eventually, after a sunday school teacher told me to read the bible "from here to here, then here to here, then here to here" before the next sunday. I instead went home and over the course of that week, managed to read the entire book cover to cover from Genesis to Revelation. When I got back the next sunday, I had so many questions about different contradictions I noticed, etc. I ended up getting scolded for reading more than I was told to (which I thought was absurd). From having the conversations where I was supposed to explain my actions, where I instead got into deep converstations with other people in sunday school and ended up in some fierce debates. I eventually developed a real knack for debating Christianity, and found out how much I enjoy it, not necessarily debating against the existence of deities (which I did still, to an extent, believe in at the time), but about problems with contradictions and issues in the biblical text.
After many years of thinking about it heavily and debating it in voice chat rooms on Yahoo (I used to go into Religion:4 every night under the name "railbuffrob") my natural desire to know facts and understand things logically began to overtake my loose faith and beliefs which I was trying so hard to continue believing. In the end, (around age 19) I began to notice my debates were moving closer to a neutral standpoint, then closer to that of the Atheists. This was my Autistic literal logical brain catching up to the years of childhood brainwashing and eventually overpowering the faith with me basically coming to the realization of "why am I trying so hard to believe something that makes no logical sense when there's something else that makes more sense and seems to be backed up with everything I learned in science classes.
The main thing that got me thinking was just the way that people take it all in blind faith and get offended when I mention that I believe the bible to be exaggerated in some places. One good example is the virgin birth of Christ, back in a time when people would believe almost anything you told them and pre-marital sex was punished by having rocks thrown at you, a woman named Mary got either raped or knocked up, and rather than telling Joseph the truth which she knew would lead to her death, she made up a story about a virgin birth which the people soaked up. See, this isn't saying that there is absolutely no god, it's just a more realistic perspective on what I read out of the bible. This theory is what got a sunday school teacher to turn albino pale and then grab me by the arm and drag me to the priest's office where she told me to repeat what I said and thus shocked the priest enough that he called my mother, who then said "well, that makes some sense".
Basically, to answer your question simply put, my brain can't handle ridiculous stories nearly as well as it can handle cold hard logic.
