I agree Autumn re the different streams.
In Flanders, there are 3 main streams: General Education (for those who want to go into higher education - it's useless for going straight into work), Technical Education (which is more specialised and can still be extremely difficult - e.g. options that focus on maths/engineering), Professional Education (wide range of vocational courses - hairdressing, woodwork, mechanics etc).
General education is just that - they expect you to do everything, and you choose some options that go deeper (e.g. languages, maths, economics, sciences, etc). However everyone within general education gets all of these subjects (+ more) to a decent level to start with.
Technical education is for those who really excel in something and are not very good at something else (e.g. great in maths/sciences but crap at languages) - they'll still get the other subjects but on a lower level.
Professional education is great if you are not very academically minded and would rather do a job rather than higher education - e.g. my cousin is a mechanic. You also get other things (like maths, languages) but it's more a basic level. In most of these subjects from 16 you do several days a week of work placement to learn on the job.
I get the impression everyone here is put through the same average stream - which is fine for average students but you end up with disruptive pupils as it's too hard for them whilst also basically neglecting the brighter ones.