re: a brief one
During that time I got my first exposure to "born again" people and got to see how people's minds could be overcome by wishful thinking and emotion to completely override their logic. Began studying the history of religions and the evolution of the Bible and saw that it was often nothing more than a huge manipulation by some humans for power and control of others. I also got to experience the alienation of someone that wanted to question things and saw how self-propagating the entire system was. Even the most innocuous sect was cult-like in that manner.
Keep in mind these things don't just apply only to religions.