I would have added to that list: [4] Teachers aren't good at lecturing. A great lecturer can make a subject fascinating. A great teacher can organize informat

I would have added to that list: [4] Teachers aren't good at lecturing. A great lecturer can make a subject fascinating. A great teacher can organize information in such a way that it fits together logically. But an average teacher does neither of these things. They are giving you material you could learn better and faster by simply reading the book. So far as I could tell, in most of my classes through grade school and high school the only reason for lecturing is that some kids can't or won't read the book, so the teacher needs to say out loud the exact same things that the textbook author said better in print. When choosing a textbook, you can use one written by one of the best subject-domain teachers in the entire country and that author has an editor whose job is to hone the material to minimize repetition and confusion. What's more, you're not even constrained to currently living textbook author/editor combinations. If the best treatment on the subject was written in 1947, schools can still use that 1947 textbook (or relevant quoted sections from it). But when choosing a teacher you need to find somebody who is alive and teaching today and lives in or is willing to relocate to your neighborhood, which hugely lowers the expected quality. Your math teacher might be quite good compared to most math teachers in your county but probably is not a world-renowned subject expert the way your textbook author is. Your teacher has no editor tightening up the prose. Your teacher's lectures are (compared to the book) rambling, poorly organized and repetitive. As a result, the best learning strategy to get at least some value out of the time you're forced to spend sitting in a class being talked at by idiots is to read the textbook and ignore lectures - use that time to read books or magazines that you actually enjoy.