I'm sorry, can you give a single example in the arts and sciences of something that has a reputation for "poor pedagogy"? (But is in fact just inherently diffi

I'm sorry, can you give a single example in the arts and sciences of something that has a reputation for "poor pedagogy"? (But is in fact just inherently difficult.) Here are some inherently difficult subjects: quantum field theory, advanced calculus, orbital mechanics. Do any of these subjects suffer from a reputation of "poor pedagogy"? I was referring instead to specific technological solutions, and, specifically, to encountering the idea that a subject "merely" suffers from poor pedagogy. My comment had zero to do with the difficulty of any subject.