We know joy when we are happy to take from life what is given. When we experience the joy of the soul and higher states of consciousness, this joy is the essence of completion and fulfillment. There is nothing that can add to it or take away from it. Joy is our natural state.
The highest point of life may be to live in a state of pure flow, a "now-state" without past or future, in which prediction and control are not factors—a state of continual, instant-by-instant adaption to the unknown.