What are some things about teaching that are surprising or counterintuitive?

Hello everyone!

Teaching is so amazingly complicated, and it's often counterintuitive.

For example, if you want your students to “do better,” you can just give easier tests. But we know that doesn’t work in the long term. What other things about teaching are surprising, counterintuitive, or are often misunderstood/underappreciated?

Let me know in the comments below—I'd love to write an article on this topic!