Discipline is the key to a happy and successful life, people say. But what defines success? After all it is just a matter of perception. What one may consider success, to another it is failure. But again, the wise will only consider failure as a stepping stone to success, nothing more than a temporary setback. So let us put it this way, success is the consequence of chasing one's dreams and then defining his life by the dreams.
Next question, how does being successful make you happy? If you define success as money and prosperity in life, then happiness will exist only in dreams. But as per my earlier definition of success, trudging the path that you long for, chasing your dream, will be reconciling to your innate desires and then you will be happy not just at the end of the road but all along the way as well.
Now, what has discipline got to do with all this? Nothing much. Just that it is human nature to relinquish dreams after a few setbacks. Think that they are wasting their time and should live their life as per the norm, safe without taking risks. To avoid this, to keep going along the tough but desired path, without discipline, you better not set out in the first place.