With small companies, it's much easier to hop to another small company than it is if you work at the only car plant in town.
And I'm sure there are restaurant owners out there who aren't complete assholes.
And I'm sure there are restaurant owners out there who aren't complete assholes.
Alternately, we could institute worker protections and support unions (which are necessary to develop the political will to institute worker protections) so they all have to treat you decently and everyone who works hard for a living can have a humane reasonable life.
And even if that isn't okay for you, there are plenty of ways to do this without even curtailing anyone's "freedoms" to be abusive: we can provide government jobs to all workers if they want them and require managers at government run institutions behave decently, for example, as we did in the New Deal.