Why do I feel like I’m constantly searching for another job almost immediately after starting a new job?

Lately, I feel as though much is promised in a job interview, but then when I start the job it all goes out the window, and I’m just completely stunned by how different the place is than they made it seem during the interview. I have been in the same field for about 8 years and what I’m finding is it’s the same BS everywhere, and I feel like as soon as I start somewhere new I see that and I want to leave again. I feel like I’m constantly being paid, to look for another job. It’s a horrible cycle, I’m aware of this. I just refuse to stay somewhere I’m undervalued and treated like shit I will not do it.