My answer is going to be outside the norm, I'm afraid, as the majority of my teaching experience is in Thailand.
My answer to the above question would be: culture.
Culturally, there are huge problems here with regards to teaching.
First of all is respect for authority. Now, it sounds nice perhaps to a teacher in a western school system that children practically pay homage to their teachers here, but the result is incredibly frustrating. Kids, and adults, simply uncritically accept anything that a teacher says on the principle that they are in authority and to disagree, or to question even for clarification, is to be disrespectful, which is, as I am sure you can imagine, very unproductive.
Trying to get either kids or adults to critically assess something is a non-starter. They don't want to arrive at their own ideas, they want to be told what to think. They want the answers so that they can regurgitate them and therefore be correct.
Which leads me to the next problem. No one can be wrong. Being wrong 'loses face'. A student would rather sit there saying nothing than respond to a direct question just in case they are wrong. This ends up with convoluted teacher effort to frame things in such a way that no one can be wrong. It's a self-defeating enterprise because they expect to be given knowledge on a plate. When I first came here, I was surprised at how many Thais knew the word 'osmosis'. That's literally how they think education works. The student sits and osmotes the wisdom of the authority figure.
As a teacher who is more interested in giving their students the tools to develop their own answers, this has been a constant struggle for me. You cannot empower people here, and if you attempt to do so, you are failing at your job.
Next is a concept called 'jai dee' - it basically means 'kind'. If you are not kind then you are a bad teacher. To be kind, you have to not expect answers from students, not complain that they have failed to do their assignment, or that they've blatantly copied their mate, or ask them to do something difficult. You are never permitted to raise your voice or show dissatisfaction at their inexcusable failure to complete a very short home assignment. Bear in mind that the vast majority of my teaching is with adults, not kids as you might have expected reading that paragraph.
Your contract with a school or educational institute largely depends on what the students say about you, so to be successful, you need to basically divest yourself completely from student failure - to notify parents, school heads, or bosses of the students inability to progress due to study problems is to put yourself squarely in the target as a bad teacher. However, if the expected educational results are not met, the failure is the teachers.
Middle-class parents are incredibly polite, but they push their kids to exhaustion, enrolling them in numerous extra-curricular educational activities rather than letting them be kids and enjoy their weekends. I had one teenage student who was nearly in tears from exhaustion and stress. She was at school during the week, had private tuition 4 nights a week, piano practice on a Saturday morning, English classes on a Saturday afternoon, and computer literacy classes on a Sunday.... and her parents were giving her a hard time for not completing her school assignments and for 'being lazy'.
Schools are extremely political institutions, with a very clear cut hierarchy that cannot be challenged. Other educational institutions are bums-on-seats, and don't give a toss about class sizes, effectiveness of teaching methods, materials... even sufficient chairs for students.... as long as they can squeeze another few baht out of a course.
Finally, western teachers here are all too often actually unqualified sex-tourists that wanted to find a way to stay, so they took up teaching. I jest ye not.
So when you next think you've got it bad - come and teach in Thailand!
