A teacher's job is hard to do well, but perhaps not so hard to define, at least partially.
A teacher's job is to motivate students to learn. This is, in my experience and without doubt, the most important single factor in the education process. A motivated student will learn, and you probably couldn't stop them if you tried. An unmotivated student will not learn, and may even actively avoid it.
As a teacher, teacher educator and education professional, who has trained and managed hundreds of new and also more experienced teachers, it always used to annoy me intensely to hear weaker teachers say "My students don't seem to be motivated to learn". I always responded with, "Whose fault is that? And what the hell do you think your job is?"
Whean a teacher says, "These students aren't motivated", it translates as "I HAVE FAILED to motivate these students."
Apologies for the slight derail. I do, admittedly, tend to have very strong views about these things! To the OP - kudos to you for your kind act of generosity and your commendable interest in youngsters' education. And to the teaching sub who thought a Squier Affinity isn't a good enough instrument to learn on, I would suggest being careful how and where he expresses such an obviously ill-informed opinion, or he's quite likely to end up embarrassing himself.
