There is no hope of joy except in human relations. (Antoine de Sainte-Exupery, 20th century French writer)
This is one of those observations that might be true but could be questioned by people with contrary experience. No doubt having strong, positive relationships with others can provide a lot of joy. But contentment can also be found in being alone reading, singing, or meditating. Perhaps joy is an internal element that is found in a variety of experiences.
Joyful is the person who finds wisdom, the one who gains understanding. . . . Those who trust the Lord will be joyful. (Proverbs 3:13; 16:20)