When you sing with a group of people you learn how to subsume yourself into a group consciousness because a capella singing is all about the immersion of the self into the community. That's one of the great feelings - to stop being me for a little while and to become us. That way lies empathy the great social virtue.
The best books for a man are not always those which the wise recommend but often those which meet the peculiar wants the natural thirst of his mind and therefore awaken interest and rivet thought.