Maybe this is like shooting fish in a barrel. Guitar teachers, educators, and performers are really easy to pick on. We make so many mistakes because we tend not to try so hard. My biggest (but most fun) mistake was signing up for Twitter. It broadcasts all of my spelling errors. I have heard hundreds of horror stories from people who I've helped play guitar. I've heard people say stuff like, "I bought this book, but it totally sucks. It's boring." Did the people who wrote those books ever stop to think that the content or it's delivery is neither appropriate or fun? Like I said, targets. We do it to ourselves.
There is only one way to teach appropriately, and that is to experiment and get better at it. Our job is not to immediately foist a Beatles song including the solo on a student who is on their first lesson. Our job is to make appropriate but fun ways to eventually help the person play that Beatles song. If you don't try hard enough, then it is easy to become a horror story, and bad news travels fast.
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As a side note, the story above about the Beatles song, solo and all, is a true story. Guitar teachers make easy targets. My Twitter moniker is @feedbackguitar