I think that a successful old age is easiest for those who have strong impersonal interests involving appropriate activities. It is in this sphere that long experience is really fruitful, and it is in this sphere that the wisdom born of experience can be exercised without being oppressive. It is no use telling grown-up children not to make mistakes, both because they will not believe you, and because mistakes are an essential part of education. But if you are one of those who are incapable of impersonal interests, you may find that your life will be empty unless you concern yourself with your children and grandchildren. In that case you must realize that while you can still render them material services, such as making them an allowance or knitting them jumpers, you must not expect that they will enjoy your company.