Will power needs to be developed with discrimination. We should be strong willed with compassion and not by being obstinate. Will power really means having the courage of your convictions. Stubbornness is sticking to your point of view even when disaster is imminent. A strong willed person may stoop to conquer or acknowledge his or her mistake. A sense of justice and fair play are the hallmark of strong will power along with a pragmatic approach to life.
The stubborn will refuse to accept and see reason. The strong willed will understand the need for adjustments and act accordingly.
Ideally proper will power should developed in childhood under the guidance of the parents. As grown ups we should set small goals and seek to fulfill them. The inner satisfaction will make the effort worth while. Try it !!