[Desafinado]

This is a good way of putting it. And whether someone is happy is indeed personal.

For me, company culture has always been a primary concern. Is the company a non-stressful place to work and am I working with grownups. That's a massive factor, and the reason I've left two previous jobs.

Laudability is also big. Or in other words purpose. Once all the sheen of working in the software industry wears off do you actually care about the work you're doing? That can go a long way in providing motivation.

But then there are some who are happy to grind out code for exorbitant amounts of money and no purpose. So YMMV.