Learning is like frying a small fish. You can spoil it by doing too much poking. Learning in fear does not last. Children learn through play. Adults play to learn.
Playfulness can be present even in serious learning.
If the learning environment is managed with acceptance, the students are relaxed and honest. If that environment is managed with repression, the students are difficult and mischievous. If a teacher seeks power, the more resistant the students. Therefore, the wise teacher is content to be an example and does not impose his or her power. Just do your job, and then let go.