Baileysx
I don't think people fully appreciate the varied levels of problems, or the impact of small problems over time.
One of the phrases I came to hate was "low level disruption". Nothing serious enough to cause a physical risk to anyone's safety, but actually really damaging to pupil progress.
Imagine a pupil in a good school, no major issues with behaviour, the students aren't at risk, and it's overall a nice enough environment. The pupil has 5 lessons a day. In a lesson, the first 5 minutes are spent getting into the classroom and resources out. Then the second 5 minutes the teacher can't get straight into the starter or the starter is interrupted because 3 students haven't got their pens, or have lost their book. Then the teacher reviews the starter, but instead of everyone listening, the feedback is fragmented by the teacher stopping to remind some students to listen to the answers. Then the teaching input starts, but a couple of students aren't paying attention or are whispering so the learning stops. Some warnings might be given here. Then the teacher explains the task and different students are talking so instructions have to be given again. 10 minutes into the activity, most of the class are getting on, but the students who weren't listening haven't done much and now argue that they don't know what they're doing. Obviously they've not asked for help or clarification, they're just talking. Now the teacher is recapping with them at the expense of supporting other students or stretching the more able. When it comes to review the answers, more time is lost waiting for pupils to listen, show respect to each other.
Repeat for an hour.
Some students will have warnings recorded on the behaviour system, but fly just low enough to avoid detentions or being removed.
Then do that 5 hours a day.
That is a LOT of lost learning time.
It's also a LOT of time a teacher is focusing on behaviour rather than SEN support, or helping learning, or stretching bright children.
When you think how much learning can be done without those disruptions, it adds up. One year I did the maths with one tricky class. It changed their whole outlook and classroom culture.