The flip side of this is when a profoundly gifted person tries to teach the whole bell curve! By the time I was in 5th grade, I'd already read 1984 and most of Gone with the Wind. As a new 5th grade reading teacher, I had no real sense of what 5th grade reading level was, or what questions I could expect 5th graders to answer.
Someone had to teach me all the intermediate steps to help students of average ability and struggling readers understand what I would have understood instantly. That was tough.
I still make mistakes. Last year, I asked my all my 6th graders to explain how the concepts of karma, dharma, and reincarnation has helped convince Hindus that the caste system was fair for centuries. This year, the same assignment will be a challenge assignment for those students who are trying to demonstrate an ability above and beyond expectations in order to earn an A.