Everyone has a hobby, but most of us never are able to devote enough time to it because we have to make a living. Mostly, perhaps, this hobby is something to blow off steam and forget the trials of your day-job. Maybe it would simply evaporate if you were suddenly endowed with a fortune.
Realistically though, I doubt it. It seems to me that what we spend our precious spare time on is, by proxy, also precious to us. Does it not follow that we would like to make money while doing our hobby—and lose the job?
Make certain you read that correctly. I said, "make money while doing your hobby." This is a distinct thing from making money by doing your hobby. The distinction lies in the independence of your hobby, and in your control over it. To make money by your hobby is to perform your skill for another person who commissions you. To make money while doing your hobby is to attract people who are interested in what you have created.
The first is dependent upon another person's permission, regardless of the freedom that person allows you. The second is dependent only on your own discovery of a good idea, and your personal willingness to execute the necessary performance.
The first is a trade—your skills for money—and therefore a zero balance. The second is a gift—you create because it fulfills you, then those who appreciate your art support you by paying you compliments, buying the souvenir, and referring you to others—and therefore goes way beyond the initial creation.