The natural state of a human being is joy. Joy is a healthy state – healthy for us spiritually, emotionally, and physically. Lack of joy comes from thinking in ways that block your joy. Different people have different obstacles to their joy. It is easy to blame other people, circumstances, or situations for one's lack of joy, but the only reason that other people, circumstances, and situations might cause a lack of joy is because of the way that one views those factors. The one who views everything in his life as an integral part of his service to the Almighty, will experience joy in dealing with whatever arises. "This, too, is part of my mission in this world."
(Growth Through Tehillim: Exploring Psalms for Life Transforming Thoughts, p. 183)