Thousands of young adults join good churches all over Faerûn every day with the hope of becoming clerics. Some find it's too hard or not to their liking, and leave after absorbing only some elements of the church's teachings. Some find other roles in the church more exciting or rewarding. More than just a choice of patron deity, these devotees of a faith identify more strongly with their church than they do with their home country.
Any region with a significantly large good temple.