I don't know how teachers do it in this day and age. I know the teachers here in the US have issues. This is a generalization, not all fall into this category, but more and more are (and teachers I know say it is the majority now), but parents are not teaching their children to behave. They give them video games and and phones and anything else, but don't give them what they really need - time and discipline.
Teachers don't have authority to discipline, either. If they have a meeting with a parent about the behavior of their child, the parent (not plural, on purpose, because so many live with a single parent) says that their child would never do anything like that.
I remember when I was in school, the teacher ruled (and the principal did if it was really bad). If we misbehaved in class, the parents (plural, because most families had both parents there) believed the teacher.
We had a genuine fear of getting caught doing something wrong.
I know children who brag about how much trouble they get into at school. They say that all it does is get them out of "boring class." Many can barely read or do simple math. They are preparing them for an adult life of living off the government or a minimum wage job (which are getting fewer and fewer).
It's no wonder teachers burn out, quit, or retire early.
Yes all that! Teachers definitely don't have much authority and parents always believe the kid. Ice had some horrible situations where a parent would be shouting at me after the kid outright lied and I said as much.
Luckily I worked in non government schools that were a bit easier behavior wise and I could actually teach with an academic focus. I'm not sure if survive in a state school these days. Most of the time the kids are gorgeous. I love teaching students, it's all the other stuff I hate. But I'm definitely done now - I won't ever go back. I'd rather pack shelves in a supermarket.