The best things in life aren't about income. For me, few feelings rival those which resulted from finding a solution to the Rubik's cube puzzle or figuring out how to place a 125 pound bat house in a tree atop a 25 foot ladder during a windstorm. All the book learning and classroom time....eengh. It is street smarts and survival which tests mettle. To see what needs to happen and make a plan to accomplish the goal is rewarding, but it is especially gratifying when the goal is achieved.
I know which brain-work I am capable of doing. Left-brain, right-brain, no-brain. Satisfaction isn't free, widespread, or easy.
