You don't need FU money to tell people to go stuff themselves, you just have to have a skill set that's in high demand and a good reputation.

Actually, you mostly need a) balls and b) the verbal skills to tell people to go stuff themselves without being directly insulting.

You would be surprised how few people lose their jobs by saying "no".

This is very true. It's a truly dysfunctional environment where someone gets fired for not willing to work un-negotiated overtime.

In either way though, there is a huge advantage to having choice - and being able to walk away from a job if push comes to shove. It affects the way you carry yourself, and it dramatically alters the dynamic between you and your employer.

The knowledge that, if things really got bad, if your boss turned out to be a giant asshole, you could walk away and be at another job in a week's time, is a tremendous psychological aid when it comes to pushing back and negotiating.