I used to work at a gas station, pizza place, delivered furniture and what not with managers that are just regular people promoted to management. They aren't trained, they aren't even slightly educated in management styles and some don't have basic people skills. And of course, they are promoted by people that are also untrained.
Most of the examples on this subreddit, are from those types of managers. They don't know how to manage properly, so they manage with fear or with force. And even the people above them manage the same way.
For the past 10 years, I've worked for a medium-sized company with properly trained, useful managers. Not all companies have great, or even good managers, and not all the managers at my company are great, but they themselves are managed well-enough by those above them.
My point is not all managers manage with fear or unethical tactics. But everyone should educate themselves on what a good manager is, and what a bad manager is.
https://teambuilding.com/blog/bad-manager-signs
The above link is probably the most comprehensive and clear list of red flags for bad management. I guess I have to say that I'm not promoting this website, nor am I affiliated with it in any form or fashion, I just genuinely like the list.