Have you ever had a conversation with a religious person in which you were able to alter their thinking?
I have a cousin who is/was a very devoted Christian. We once had a quite rational discussion about religion and his beliefs. I posed some questions that pointed out some of the inconsistencies in religion. At the time he responded in much the same way as you might expect. But then, roughly 15 years later we were talking on the phone and he mentioned that he had often thought about that conversation, and it made him question his beliefs. Needless to say, I was pretty stunned.