It’s easy to tell when your kids don’t like a gift. Three-year-olds just don’t have the grace to tell Grandma they’d rather have a Transformer than yet another pair of pajamas. They just throw it across the room and then go and pout behind the Christmas tree (unless you’ve managed to teach them some manners by then).
But at some point in our lives, maturity requires we be a little more civilized. Sure, we may not like/understand/be able to identify a gift, but grace requires that we smile and be grateful anyway.
Thus, Present Face.