The rules of engagement as evaluated by Mihaly Csikszentmihalyi outline the ability for individuals to become absorbed in a single activity while losing time. This is due to the pleasure that one experiences that places them into a state of flow and personal satisfaction.
Mihaly Czikszentmihalyi discusses the secret to happiness and how people determine what makes their life worth living. Involving oneself in an activity that brings oneself pleasure will help to bring about the state of flow. Monetary gains can not make us happy alone.