It matures us as individuals, teaches us profound lessons in life and enables us to take nothing for granted. It also earns us the fellowship of our fellow human beings and makes the world a better place to live in. Experience is the best teacher and some of the lessons we learn in life we would never learn in a classroom.
Knowing that you have earned it brings a new sense of rejuvenation to you. You appreciate what you have worked hard to earn - you may not really feel the same way about gifts you have received even though you may cherish the gifts. The smallest amount of money is that much more significant when you have toiled hard for it. A fortune may not mean the same thing, even if given free.