Before I was a software developer I was an auto mechanic and this ethic is what makes the good people good in both fields. Sure, you can make decent money doing flat-rate brake jobs that pay 1.5 hours in 30 minutes, but if you like to fix cars, you crave those problems where you've got to dig deep and experiment, and are more concerned with solving a challenging problem than what the $/hr turns out to be for that job. In an auto shop, the people who are willing and able solve the hard problems when they come up generally get assigned the best(easiest to finish under book time) of the other work. From what I have noticed in both fields, the happiest and most successful people have a sincere interest in their craft (knowing how, and wanting to know how things work), and this interest often carries over into how they chose to spend their personal time.
