Use of a parental title by lay people further infantilizes the people of God.  Most priests address parishioners by their first names and yet the parishioners respond with the title.  It shows a large power imbalance present between the pastor and the people.  Our culture is largely on a first name basis, and I see no reason to elevate priests to the level some believe they deserve.  Another sign of clericalism and elitism that needs to be examined.