I answered this question: Atheists, how did you become atheists?

"Atheists, how did you become atheists?"

Age 18. The pastor spent the entire sermon, two Sundays in a row, explaining why we needed to donate more of our hard-earned money to the very wealthy Vatican. That's when I realized the Catholic Church is not a religion. It's a business and the customers are suckers. That was the last time I went to church. 

Because of the intense religious brainwashing I had to endure at a Catholic school it took me a few years to completely throw out the ridiculous god fairy fantasy. Eventually I educated myself about science, especially evolution, and now I'm a hardcore atheist, 100% certain magical beings (Easter Bunny, Zeus, Allah, leprechauns, God) are not real. 

I'm hardcore atheist and extremely anti-theist. Also I am anti-agnostic. Agnostics are idiots. They are too dense to grow up and make a decision.