In my humble opinion, one of the hardest things about teaching is that explanations that make sense to me today would not have made much sense to me with what I knew 30 years ago.
There is so much background information in our current understanding, that we tend to forget how it felt to learn our topic the same time.
This reminded me of one of Brian Eno and Peter Schmidt’s Oblique Strategies cards: “the most important thing is the thing most easily forgotten”.