Tectime, I certainly hope you don't come to regret your words. I sat O' levels during the so called Golden Age and I can tell you they were basically a memory test. If you did no work during the course and crammed the night before you could get good grades - I am proof! It is good for lazy people who have the ability to memorise and write woffle in a convincing way for two hours but not necessarily for the average hard working studious person.
We must be lucky, I have come across one or two teachers in the state sector I disliked due to personality but I have never encountered an incompetent teacher in my own state school days or in my daughter's state schools. I did come across incompetence in the private sector; but paying peanuts attracts monkeys I suppose.
My DD has just done her GCSEs, they test in much more breadth and depth than O' levels ever did. She has also done 11, more than the 8, I sat which was standard in those days. We are both grammar school girls!
In respect of your earlier posts about the superiority of the Far East's education system - I previously worked at a well reputed Uni in central London. I found many students from that region to be utterly incapable of analysis and forming their own opinions, all they could do was memorise and regurgitate. We tried to help them but it was often too late to develop those skills. While saying that, most of them passed because the Uni wanted the overseas rate fees! Which is another scandal quite frankly.
My sister has taught and is currently an academic author (in English) working in a Far East country. Her experience is that the day to day teaching is often poor and secondary age kids (apparently the majority) have to go to night classes to cram for their exams.