Since there seem to be a number of threads in this spirit, I'd like to ask how others became atheists. For myself, I learned some things that made me understand the Bible wasn't true. I looked deeper, and it became even more unlikely. Well if not the Bible god---who? My goodness this world is full of gods and belief systems. All culturally specific---all changeable---all very limited. And when I looked at science, I saw that a god was not acutally necessary. I mean---how could all this exist without a god? Science showed me it could.
Then I paid attention to how believers expressed themselves. I saw with everyone of them a kind of denial to evidence---a certain amount of acrobatics their brains did to force everything to fit into their belief systems. It was uncomfortable to watch and continues to be.
Of course, this all seemed to happen in less than a minute, for me. But when I broke it down, I realized I had been doing this for about 2 years before I concluded there was no God. I, as a believer, was also doing mental gymnastics to frantically make everything fit, and in that moment it no longer fit anymore. That was when I was really able to solve the puzzle.
NC