You have a job, right? If your employer solves a useful problem for its customers at a reasonable price, obeys the law and treats its employees and suppliers fairly then it is doing good and you are doing good through it. Do your work conscientiously and go home happy.
That's assuming "giving people what they want" is inherently good, or worse, the only good. It is neither.
People getting what they want is neither good nor bad; it is effective at distributing resources. But this is distribution isnt inherently good either (effective != good).
We don't need to define "Good" in order to observe this. Very few definitions by anyone, let alone OP, produce this equivalence.
I agree with you. It's quite possible to make money doing pernicious things. It's even possible to make money legally doing pernicious things. And that's why I'm setting the bar considerably higher. Note my words: "useful problem", "reasonable price", "treats ... fairly".
No. This is you not understanding that while this answer has huge caveats attached to it, it is also a solid point worth talking about and taking into account. A lot of "mundane" jobs are actually socially beneficial in some way.
