Some people need a teacher for the deniability of following instructions. "If you do what I say, you will not get in trouble."
Some people need a teacher for the authority of someone giving them orders. "I'm the boss here and you wouldn't survive without me."
Some people need a teacher for the comfort of avoiding fear. "You don't have to be afraid - I'll take full responsibility for your actions."
Some people need a teacher for someone showing them their mistakes. "You don't have the education and the experience to know what's right or wrong."
Some people need a teacher for the pleasure of giving them credit when it's working. "You did a good job today. Try even harder tomorrow."
Some people need a teacher for the stability of knowing what to do next. "Here's the manual. Look on page 23 and do step 4."
But of course, that's not a teacher, that's a manager.
Other people, though, need a teacher who would get out of the way and trust them to have the courage to change everything. "I haven't seen you making enough mistakes lately. I want you to do more of them, please."
But of course, that's not only a teacher, that's an artist.