Yesterday I had the great joy to share Christ with someone. The opportunity just came up naturally and I did not force anything on the person ~ I simply shared my own experience. He shared with me too. It turned out that he believed in God, but not in any particular church. When he was around 6 or 7, after some tragedy struck in his family, he got really angry and looked up into the sky and yelled at God "Why did this happen?" or something like that. Then he heard the rumble of a thunder and it was on a clear day. I told him that the Lord was probably letting him know that he heard him.
I have heard or read other similar stories. You just don't forget incidents like that and eventually the person comes back to the Lord and/or the Church. There are no accidents!