Another interesting article from the Jesuit prayer site my own grandmother is a member of.
“Being a grandparent has many bonuses. It is more agreeable than being in charge. You shed the power of authority, and also shed the distance which it imposes. Children use their grandparents in a particular way. They can be very direct and contemporary in their comments. A friend was telling his granddaughter a story when she interrupted, ‘Fast forward, please, grandpa.’ Grandparents can be safe people to talk to. Children know they can count on affection, and need not fear retribution if they tell things the way they are. In return children give their grandparents a joy that compares with that of parenthood.”