If a man strives for sublimely great ideals, it is because they are the content of his own being, and their realization will bring him a joy compared to which the pleasure that a limited outlook gets from the gratification of commonplace desires is a mere triviality. Idealists revel, spiritually, in the translation of their ideals into reality.
Anyone who would eradicate the pleasure brought by the fulfillment of human desires will first have to make man a slave who acts not because he wants to but only because he must. For the achievement of what one wanted to do gives pleasure. What we call good is not what a man must do but what he will want to do if he develops the true nature of man to the full. Anyone who does not acknowledge this must first drive out of man all that man himself wants to do, and then, from outside, prescribe the content he is to give to his will.
Man values the fulfillment of a desire because the desire springs from his own being. What is achieved has its value because it has been wanted. If we deny any value to what man himself wants, then aims that do have value will have to be found in something that man does not want.
Source: Rudolf Steiner – GA 4 – The Philosophy of Freedom – Chapter 13: The Value of Life
Translated by Michael Wilson