When I was a schoolteacher, the way I expressed this is that you have to do the job in such a way today that you're capable of doing it again tomorrow. This did not go down well and I am no longer a teacher.
Here, by "job" I mean the traditional kind at a corporation or medium-sized organization. After seven years of working in such organizations I realized the only thing that was fulfilling was quitting and doing a bunch of random things like contracting, content-creation, and other passive income streams.
Of course, that may not be for everyone but I still think (after talking to hundreds of colleagues in various places) that after a while, most jobs suck. Sure, some of them pay well but then again, I personally feel that no amount of money is worth spending the best part of your youth doing mostly meaningless things. And, if the money IS good enough, it makes sense just to work for a decade and then retire early...
It depends on why you’re doing it. Supporting a family, and contributing money and spare time to your community, are very meaningful. I’m building <yet another API> for <Company> in order to do my real job which is being a parent and citizen.
If the job you have genuinely doesn't allow you to do your real job (support a family etc) then you're definitely in the wrong job.