The development of self-discipline is like exercising a muscle that develops the more you use it.
No one achieves mastery of a skill, competence in a profession, or knowledge of a subject without hours and hours of effort, frustration and setbacks. Natural gifts — intelligence, size, strength and quick reflexes — are a bonus, but rarely sufficient to achieve the highest level of success.
Here are some levels of mastery that few manage to reach:
Dispatches From The Front 