Hobbyist, Professional, Craftsman, Artist

For any given activity, I propose the following operational definitions:
One who pays money to do the activity.
One who gets paid to do the activity.
One who sweats the smallest of details involving the activity.
One who transcends the activity and uses the activity as a tool to communicate higher level ideas.
The only two that are mutually exclusive are hobbyist and professional.[foot]Though even this is debatable. One could pay for personal projects while receiving payment for client projects.[/foot] I don't necessarily see them as hierarchical. One very well could be an artist hobbyist. There are numerous aspects of involvement in anything; these are an attempt at classifying those different types of involvement.