From Robert Pirsig's Zen and the Art of Motorcycle Maintenance:

And that door leads to Sarah's office. Sarah! Now it comes down! She came trotting by with her watering pot between those two doors, going from the corridor to her office, and she said, "I hope you are teaching Quality to your students." This is a la-de-da, singsong voice of a lady in her final year before retirement about to water her plants. That was the moment it all started. That was the seed crystal.

Quality... you know what it is, yet you don't know what it is. But that's self-contradictory. But some things are better than others, that is, they have more quality. But when you try to say what the quality is, apart from the things that have it, it all goes poof! There's nothing to talk about. But if you can't say what Quality is, how do you know what it is, or how do you know that it even exists? If no one knows what it is, then for all practical purposes it doesn't exist at all. But for all practical purposes it really does exist. What else are the grades based on? Why else would people pay fortunes for some things and throw others in the trash pile? Obviously some things are better than others... but what's the betterness?... So round and round you go, spinning mental wheels and nowhere finding anyplace to get traction. What the hell is Quality? What is it?

So Google it. It won't help. Put quotes around it, "teaching quality" and you will find that everyone is concerned about the quality of teaching, but few care about the teaching of "quality." Putting wood in the hands of students, demonstrating how they can attain quality in their work, noticing when they do, and giving them the chance to do it again and again... it becomes a habit that grows beyond the woodshop.