I very recently learned a damned hard lesson in this. I believed in the product, I was given interesting problems to solve, there were good benefits, there was a good culture, I had stock options. The pay was shit, the options evaporated during a merger, and I want to buy a home.
Next round, I'm getting paid my worth and it's going to remote. "Believing in the product" is just a load of bullshit that C-suite spin to enrich themselves. They believe in nothing but their own bottom line, so why shouldn't you? Figure out what you are worth, what working conditions (overtime etc.) you can tolerate, and do good work for good money.