Apostasy - the short version
It started with anger over the way my Catholic Church handled (or mishandled) the priest sex scandals.
My questioning the actions of the Church leadership, while alone not enough to make me lose faith, did prompt me to seek answers to other, more fundamental questions, like "Where does the authority of the Church come from and why did they fail so badly in this case?"
In my searching for answers, I did a LOT of reading and soul-searching, and I eventually came to believe that the Church was not, in fact, founded by Jesus. While this may not seem like a big deal (I am convinced one can have this view and still be a catholic), it was a big turning point for me because it showed me just how much of Catholicism I had accepted uncritically. After that "revelation", I began to question everything from the teaching authority of the Church, to major dogmas (Mary, the Trinity, the Holy Spirit, etc.). My research wasn't based on just non-catholic sources, either, I read many catholic apologetical works along with the Catechism, and I believe I weighed all the information fairly before coming to the decision that, for me, Catholicism no longer made sense; it no longer had relevence for me.
Upon losing my faith in the Church, I began questioning my belief in Christianity using the same methods of researching both sides. Again, the result was a loss of faith in the Jesus story.
What followed was the inevitable examination of the question of God. Of course it all boiled down to the big question: Does God Exist? It took a lot of introspection, and quite a bit of research examining the philosophical arguments for and against the existence of God. The search through philosophy was inconclusive, as I didn’t consider myself sufficiently familiar with the arguments to say with certainty which side made the best case. I then considered as much objective, empirical knowledge as I could manage, and it was there that I found little support for the existence of anything beyond the known universe. Did that answer the question? Not really, but it did leave me with enough information to determine that, while I could not know with 100% certainty whether God exists or not, the fact that God, if he existed at all, was so well hidden, his interactions with humanity (answering prayers, miracles, etc.) were so well disguised as to be indistinguishable from mere chance, and the universe seemed to appear just as it would if it had not been created, that it was just as if he didn’t exist at all. In the end, it seemed that God, if he existed, had made himself irrelevent.
So, I had to ask myself, why do so many people believe?
Eventually, I came to understand there are at least two big reasons for religious belief, and neither are very objective. Most people believe because it is what they were taught as children, and don't have any reason to doubt what they were taught; they have an underlying assumption of faith which goes largely unquestioned and unchallenged.
Other people have faith because of what they perceive as personal encounters with the Divine. Reason and logic and proof come into play as a means to describe and convey a sense of that experience to others. Because of this, it is impossible, in my view, to "prove" in an objective way that there is conscious existence beyond death, that the soul is real, and that God exists. One first needs faith to believe such things.
All the decisions to believe in God, Christ, the Church etc. must therefore be based on faith. I was forced to conclude that I no longer had that faith (if indeed I ever had it in the first place).
In that moment I knew I was an atheist.
I don't claim to "know" or even "believe" that God does not exist. I only claim to have no belief in his existence based on what I know and have learned about the world.
I do not regret leaving the Church, Jesus, and God. The world and the universe are subjects of great wonder and curiosity to me, far beyond what I ever felt towards my faith. And my brief life is even more precious to me now that I know it is the only one I'll ever have.
That's the short version of my apostasy.