Comment by a96

One problem with programming as a job is that you have to work on the project (and with the tools) that your employer or customer wants you to.

On side projects, open source etc, you get to work on projects (and with tools) that you care about and/or want to use or work on.

This kind of thing probably applies in some other jobs, but not all. Music, writing, visual arts and design, and construction at least seem like something where the particular target or process may be a vital part of the interest and satisfaction.