The discipline you learn and character you build from setting and achieving a goal can be more valuable than the achievement of the goal itself.
It doesn't matter whether you are pursuing success in business, sports, the arts, or life in general: The bridge between wishing and accomplishing is discipline.
A disciplined mind leads to happiness, and an undisciplined mind leads to suffering.

The Art of Happiness
What is discipline? Discipline means creating an order within you. As you are, you are a chaos.

Yoga: The Alpha and the Omega
For discipline is imposed not just on oneself but on those in one's orbit.

Exit Ghost
Man must be disciplined, for he is by nature raw and wild
Right discipline consists, not in external compulsion, but in the habits of mind which lead spontaneously to desirable rather than undesirable activities
It is one thing to praise discipline, and another to submit to it


On Anger: "For every minute you remain angry, you give up sixty seconds of peace of mind."
On Destiny: "Our destiny exercises its influence over us even when, as yet, we have not learned its nature: it is our future that lays down the law of our today."
Human, All Too Human
On Friendship: "A crowd is not company; and faces are but a gallery of pictures; and talk but a tinkling cymbal, where there is no love."