These things don't just come, arrive and settle like a bird picking up a few bits of crumbs. They develop. I think the best word for these things is develop. They develop because of the human beings who just happen to be there at the time.
In the ideal classroom, the teacher is either spending all of their time doing deep interventions with students on a one-on-one basis or facilitating true interactivity - labs, simulations, projects.
