Many common problems are caused by wrong attitudes. People see themselves as the center of the universe and judge everything as it relates to them. Naturally you won't be happy that way. You can only be happy when you see things in proper perspective: all human beings are of equal importance in God's sight, and have a job to do in the divine plan.
Peace Pilgrim: Her Life and Work in Her Own Words (ed. Friends of Peace PIlgrim, 1992) - ISBN: 9780943734293