One component of enjoyment in any activity has been called "flow." This is a mental state in which you lose yourself and become totally immersed in the activity. Below is a neat summary of what "flow" as a mental state requires. The name and initial research is credited in Wikipedia (link in title, and source of the quote), to Mihaly Csikszentmihalyi.
Components of flow
As Csikszentmihalyi sees it, components of an experience of flow can be specifically enumerated; he presents eight:
1. Clear goals (expectations and rules are discernible).
2. Concentrating and focusing, a high degree of concentration on a limited field of attention (a person engaged in the activity will have the opportunity to focus and to delve deeply into it).
3. A loss of the feeling of self-consciousness, the merging of action and awareness.
4. Distorted sense of time - one's subjective experience of time is altered.
5. Direct and immediate feedback (successes and failures in the course of the activity are apparent, so that behavior can be adjusted as needed).
6. Balance between ability level and challenge (the activity is neither too easy nor too difficult).
7. A sense of personal control over the situation or activity.
8. The activity is intrinsically rewarding, so there is an effortlessness of action.
Not all of these components are needed for flow to be experienced.
The interesting links and bibliography to the Wikipedia article show that researchers are looking at flow in sport, gaming, spirituality, stand-up comedy, and the workplace.
The beautiful photo of Sweet Creek is from http://www.callofthewildphoto.com/