A thought takes a moment of time. A life has only so many moments. To waste thought is to waste life.
Aphorism 26: On Controlling Thought.
Be wary of controlling and blocking thought. Of course reject depression and ignore rampant desire. But grasp the mind too tightly and you deny it the opportunity to soar into the realms of inspiration.
Aphorism 20: On Thought.
Thought is energy. To waste thought is to waste energy.