Flow is being completely involved in an activity for its own sake. The ego falls away. Time flies. Every action, movement, and thought follows inevitably from the previous one, like playing jazz. Your whole being is involved, and you're using your skills to the utmost.
The true value of a forest cannot be measured in board feet alone.
Mistakes can be corrected by those who pay attention to facts but dogmatism will not be corrected by those who are wedded to a vision.
The only disability in life is a bad attitude.