Ambition can be powerful. Ambition helps a person mobilize his resources. Ambition enables someone to face challenges and persist. Ambition prevents a person from giving up.
A person with a high degree of ambition will be able to accomplish much more than someone with similar intelligence and skills but without ambition.
Ambition enables a person to overcome laziness and a tendency to procrastinate. When you have an authentic ambition to excel in a certain area, you will put in the necessary time and energy to gain the knowledge. You will have the energy to practice the skill you want to perfect.
Ambition helps you overcome potential obstacles that might get in the way. The stronger your ambition, the less any obstacle can deter you from proceeding.
([From Rabbi Zelig Pliskin's book: "Taking Action" - pages 86-7] (Artscroll.com)