Anyone who has reared children knows how early in a child's life covetousness emerges. When we lived in India I remember giving my son Steve an expensive knife. It was something he wanted and needed, and he was as happy as a lark with the gift. One day he came into the house crying. Tearfully he told me his playmate had been given a knife with two blades on it.
Covetousness is a mirage that produces wretchedness.
It fixes our gaze on something we do not have, so that we don't praise God for what we do have. God created our hearts to be satisfied only by fellowship with Him. Anything less will not truly satisfy us. Covetousness is idolatry because it places a substitute for God in our hearts. Therefore the tenth commandment brings us back to the first commandment because covetousness puts a false god in the place of the true God in our lives.