The harmony has two facets.
One belongs to the author who arranges the elements into a harmonic structure.
The second belongs to each element which finally will be a member of the harmonic structure.
For the first, the harmony is primary a proportional structure with a rigid nature.
For each element of the harmony, it should mean only the presence of another element beside it.
The human beings share in both kinds of harmonies. The social habits make the individual persons to look for coexisting with each other according to some rigid laws. The personal approach of other people makes someone to take the persons surrounding him as the first source for finding a way of agreement.
In the last case, the harmony is far from being clearly exposed. Like the musical notes which are finally caught in a harmonic relation, two persons might be part of an inequality: parents and children, husbands and wives, clever and stupid friends, and so on. Such inequality releases many times in the form of huge disagreements. However, if its members feel themselves under the compulsion of the need of being together as the elements of a harmonic relation, then those disagreements still seems to be preparatory means for a peaceful future. Sometimes, they keep on being preparatory all of our life.
Meanwhile, if we try to solve the disagreements by imposing common standards of harmonic relations between humans, it disappears the feeling that we need each other. The peaceful state is acquired faster, but it has the rigid nature of a harmony which does not belong to its members in a personal way. A perfect and respectable father or a devoted and respectable husband is not so to his children or wife, but to social standards he tries to fulfill.