The fifth commandment elevates the special relationship which every one of us has with our own parents because of the way that God has ordained that we come into this world. He gives them a heavy responsibility and an instinct to nurture their children as dependents for many years before they can handle life on their own without parental support.
So is the attitude of many to their heavenly Father. We cannot calculate what we owe him and how we ought to thank him, but the Parable of the Prodigal Son depicts the attitude of all unconverted people to God. We want his gifts, but we will not even admit he has given them. We wish he was dead, removed from his throne, and that he would stop demanding gratitude from us and leave us alone to enjoy life.