It is one of those moments parents hope for, even dream about. But it is one of those moments parents are never quite sure will ever come about. It is the moment when you pick up your child from a play date, or birthday party, or sleep-over, and the parent hosting the event declares how well behaved and polite your child has been.

Suddenly all those countless drills and dramas about saying “please” and “thank you” or “take turns” or “share” or “be kind to others” are rewarded. It is good to know that even when you are NOT looking, even when you are NOT “hand’s on,” that the long arm of loving influence and life-lessons continue to bear good fruit in the world.

Children are not born with good manners. Children are not characterized by congenital civility. One of the most common injuries i…