When Max von Stephanitz created the German Shepherd dog he wanted to breed the most versital herding - working dog in the world. I feel he acomplished this creating a dog that can excell in many areas. In the begining he searched out dogs with the HGH title or herding degree which is earned in the field with much competition. He sought out greatness and quality that sets certian dogs apart.
If you breed for only one facet of the dog you will loose the total dog. All things must be considered in the breeding pair. The idea is to breed healthy dogs, (both mind and body) and improve upon the parents. The most valuable of all qualities in the home setting is nurturing and protecting.