A quick google informs me that the USSR has a split system of senior schools.
So I get the impression that everyone attended primary and then students could go to various specialist schools - some of which were special schools for students with disabilities, some of which were intended to prepare students for in or semi skilled work, some of which fed into universities.
I have spent time in China which has what sounds like a similar system. Culturally in China it is unheard of to verbally or otherwise challenge the teacher. So they do not have the behaviour issues that the U.K has.
However children still fall behind. They sit at the back of the (big - 40 or more) classroom and fall asleep and don't take any part.
Many others simply don't go.
The Chinese system is more complicated because not everyone is entitled to a state school place so many use cheap private schools rather than have their child not be educated.
I'm going to guess that you went to a pretty decent secondary school if you are in the UK now. Apologies if I am wrong. In countries that split children up at secondary schools the schools for high attainers always have better behaviour than the schools for low attainers.
Germany for example splits children at secondary level and children can go to grammar or technical school or what is essentially a secondary modern. The grammar school experience is very different to the technical school one.
The UK used to have this system but now we have comprehensive secondary schools that are for everyone. This, combined with the lack of respect in the UK for teachers, means that behaviour can be very bad.
This is a very different culture. I agree with others that you would benefit from watching one of the tv series where they have filmed in a real secondary school for a year.