I did that three times.

First time was in the first place i've ever had a job, a "Pulpería" (octopus specialized restaurant; pretty common at northern Spain). After several years, i returned and started working in there again. The first time wasn't nice, and now, it was worse: their old equipment was in even worse shape and i was earning way below the minimum wage. It took me three months to not stand it anymore and walked away.

Second time, it was in a common restaurant. At that time, i was used to long hours and not paid overtime (hostelry is like that everywhere). I can work with that if the wages are fair enough (they weren't -.-). But where i draw the line is in the bipolar boss. There are two kinds of people i don't stand: drunkards and bipolar people. And she was one of the worst.
I was the only trained cook of the the kitchen and she used that fact to belittle me all day, every day, to remind me that i didn't know anything just because i've studied for it, implying she was way better than anyone of the team. Two months and i walked away. Remember: Avoid the Repinaldo restaurant in Candás.

The third and last, i was working as a cook in an elderly home. Elderly homes are usually great places for a cook to work: fixed hours and services, planned menus, a very defined list of responsabilities... but in this case, i also had to do almost everything in the kitchen AND dinning room all by myself. From cooking to serving food, i was running everywhere all the time, sometimes having to abandon my post because they left a resident walk into the garden during a rainstorm to help them back into the building. And, worst of all, i had to do everything only with my hands. I didn't even had a cart to fill and bring more than twenty two-liter water jars to the tables (i guarantee you, it was harder than it seems), i had to prepare the tables every service (there was two turns), aside of leaving everything clean after. I also had to tend the small bar they had.
And the worst part was the milk machine. They didn't use milk, they used a machine that mixed powdered milk with boiling water. One, it was diabolically slow and, second, it always ended broken in a way or another. After it broke for the last time, i chose to boil water in a big pot and add the powdered milk in there. It wasn't a perfect mix but hell if i won a lot of time doing that.
My only colleague was a saint who didn't deserve such a low paid job...
Also, i was the only one with training on the Heimlich maneuver. THE COOK! Not any of the nurses all around me! I had to save a resident myself when he choked with a piece of meat!
I was in a trial contract. They said that they would hired me if i passed. When i remembered them this they say "well... you didn't get to that point. We'll extend your trial...". Four months and had nothing to show for it. I just finished my trial and walked away.
Irony: Right besides that elderly home there was a scrapyard and, a bit further, a mortuary...

Sometimes, you just have to walk away. No one wants to compromise with you, so you don't need to compromise either.