People tend to complain about how there aren't good math teachers.
As I see it, there a few reasons why, in general at least, this is true—yes, I am one of the people saying there aren't many good teachers. There are obvious exceptions of course, but there are so many not good teachers that every student encounters them on a semi-regular basis. And really, I'll be assuming that teachers have good intentions and have the base level of talent required to teach that can't be taught. Not all teachers have both of those, so everything I'm about to say is skewed up, and it's actually even worse than I am presenting it.
I'll only be talking about math of course, but I think my points apply globally to all subjects.
Before we get started, I am not a good teacher. Don't get me wrong, I am arrogant enough to believe I am a fantastic lecturer or explainer—I usually assume I'm the best at explaining—and that's usually enough for me to get a significant portion of students to claim I am the best math teacher they've ever had, but I am definitely not a great teacher, so if I am the "best they've ever had", then what does that say about everyone else they've ever had?
(1) Teachers aren't trained appropriately. They need to be able to regurgitate a base level of education training and mathematical training without any sort of conceptual understanding being demonstrated in order to get teaching certificates.
You might hem and haw, but this is a fact. If you're able to do the material that you expect students to learn at around 80% ability, then you can probably get a teaching certificate with the appropriate degree.
(2) Teachers aren't compensated appropriately financially. At least not nationwide, there are definite exceptions to this on a state-by-state or even district-by-district basis, but in terms of the amount of work and training that goes into teaching well compared with the amount of compensation teachers receive, there's usually a pretty big discrepancy. This is frequently why a lot of people go into teaching because it's what they want to do, but are forced to find other work because they can't support themselves on teaching salaries.
(3) There's not enough time in the day. Especially at the secondary levels, I think this has a LOT to do with good teachers. I believe there are probably many people currently teaching that are CAPABLE of teaching well, but we're talking about planning out 6 hours of quality education every weekday, assessing and grading all of that work. There are many resources, and there is frequently the ability to re-use past years of work as long as the text or curriculum hasn't changed, but to have quality education, it's straight-up time consuming. Then you add that to that #2 and it's just not worth killing yourself over it unless you're doing it as a public service and not just a career.
(4) Teachers aren't compensated appropriately psychologically or emotionally. If a teacher is hard and you have to learn a lot, they're usually one of the least recommended and least liked teachers by a majority. Now, there's the minority of people that go to school wanting to learn, and those students gravitate to those teachers, but the harder a teacher tries and the more effective a teacher is with their assessments, then the more likely it is that students are NOT going to respond well to that.
Imagine you have a teacher that is well-trained, doesn't worry about finances and kills themselves burning the candle at both ends creating quality education both in and out of class. Then the students that appreciate you go on their way and maybe tell others how wonderful you are or if you are in a university setting try to take you for multiple classes, but most students you never hear from again. Those teachers hear about the problems students have with them time and time again however.
Personally, I have a very difficult time with criticism to be honest. I don't know what exactly it is, but no matter how many students profess to have had their lives changed by me, or say that I am the best math teacher they've ever had, or recommend me to other students who then tell me about the recommendation, or go and tell the people that work in the math department, or write glowing reviews in the anonymous semesterly reviews...no matter how many instances of great reviews there are and no matter how trivial the criticism, it still affects me to be criticized negatively.
Even when I know I'm completely right and that I have an awesome day or class or semester, when there are 20 reviews telling me how amazing the class is, 15 reviews telling me the class is fine and 2 reviews telling me that I'm terrible. It's the 2 that I am going to remember.
I don't even read my reviews now because it's not productive for me anymore. The last semester I read them I had something like 100 reviews and out of those 100 there were only 2 reviews that had anything negative to say. Guess which ones affected me the most?
Here's the thing with teaching, at least how I see it. When you put forth time into trying to help others, it is almost impossible to not care about them. Unless you're able to just completely detach yourself from what you're doing, then you're going to care.
And if you care, then you're not going to have too many instances where there is any feedback whatsoever going into that caring and chances are if there is feedback of any nature, it's only going to be negative. So you learn to cherish the positive and let go of the negative because you're perfect and this is a Disney show where you're somehow able to do that, right?
But chances are that you're probably going to start detaching yourself from the students or burn out and change careers. You're not going to make their victories your victories or their failures your failures. You're going to go to work, put in the minimal amount of effort, reuse someone else's work and assessment, stop awarding partial credit, stop encouraging or even valuing participation, get your paycheck and go home.
It's a definite cognitive dissonance situation. If you were paid well enough to put up with that bullshit, then maybe you could manage being awesome without being hurt. If the job was easy enough that the pay didn't seem like a slap in the face and you could go up there and just present without having to worry about engagement and correctness and everything else, then it wouldn't matter what you're presenting.
But the job isn't easy and you're not paid well, and it does matter what you present.
Teachers that want to do a good job are beaten down financially, emotionally, and physically, and then have to rely on the teachers they had in school and university levels to provide them with the training necessary to be capable of being a good teacher. I'm amazed by teachers that are able to overcome the first three, but even they still have that last hurdle that's more than anything else a matter of luck. And it's also split into two parts: are they well trained in the education part AND the subject specific concepts? or just one?
So why is the "average" teacher not a good teacher? Because you get what you put in. If you increased the financial incentives, there would be more talent attracted to the market and more competitiveness for positions; if you decreased the physical toll and reduced the number of hours teaching and increased the number of hours of prep, teachers wouldn't get burned out from lack of sleep and would have more time to plan projects, assignments and be willing to grade them; if you thanked your teacher and let them know they made a difference in your life and every once in a while (can be years or just when you randomly think of it) dropped them a letter or email thanking them or reminding them of the difference they made with you, then they'd be more driven to have the motivation to be a good teacher; and finally, if you offered training that made sense and taught the subject the way it should be taught and not the way it's always been taught, then you'd have teachers that were capable of being good teachers if the will and motivation were there.
But if you're a teacher in America, chances are you're not paid well; it's surprising to hear from past students, let alone something positive; you end up reducing the amount you teach in class to try to save your body so that you have time to sleep and get the papers graded; when you get behind you give free days or study hall days or you fall ill because your immune system is damaged from not sleeping (or you assign work straight from the book, teach straight from the book, and use hastily constructed multiple choice assessments); and finally, you've been a product of a system that's been like this for a long, long time.
68% of the teachers you're learning from have been "average" teachers and an average teacher isn't a good teacher.
Are the 16% of teachers that are above average enough to inspire you to greatness or to buck the trend yourself? Or are the 16% of teachers below average enough to make you swear off the subject entirely or at the very least, develop some deep-rooted inaccuracies in your understanding of the material?