Tangential to the original question, just want to note that having such realizations constantly is one of the primary benefits that accrues if you expend the energy to constantly keep yourself in a learning/teaching mindset.

The primary global benefit of teaching, in my experience, is that it keeps us jaded experts constantly at the entry point to our field. Close to the basic, foundational material. Making sure that it’s easy for new people to join, because that’s how the field grows and it’s good for everyone in it.

The primary local benefit, to the teacher, is that you have moments like this that allow you to constantly refine your worldview to be more congruent with reality. This allows you to better define what should be taught, and how.