The majority of my work experience has been in fast food, and I've worked at McDonalds before.
One thing I can say about working in fast food is it doesn't matter what company you're working for....it's the management that matters. Some fast food managers are relatively chill, but there's a lot of REALLY neurotic and power tripping ones.
If you're working at a fast food joint that's 24/7, you will probably have 1 general manager and 3 assistant managers. Statistically speaking I can tell you that at least one of them will be a power-tripping neurotic asshole. Some places have positions in between regular employees and assistant managers...they only pay slightly above what a regular employee gets and its additional responsibility but with no real power. You usually don't have to worry about those guys, but every once in a while one guy gets "promoted" to that position and becomes an asshole.
But really it's the main 4 managers you'll have to worry about. A really neurotic manager can make your life a living hell. They over-complicate shit and create more problems. What's worse, is these types tend to be "workaholics" and a lot of them will pop-in when it's not even their shift just to stir up shit. Just writing this post is spiking my cortisol levels.
The thing is, assistant manager in fast food is the absolute lowest job in the entire economy where you actually have power over other people, so naturally it attracts a lot of power hungry and neurotic but incompetent people. Also because of this, the decent managers are more likely to leave. If they're good at their job and are alright to work with, they'll move on to something better, like being an assistant manager at a supermarket or something (literally any management position you can think of is better than fast food, and pays better too). But the neurotic micro-managing control freaks will stay forever and ever so they can continue to boss around 18 year olds.