Every sign of comprehension coming from a young student is like pure gold. The other day there were two such signs: a great day.
The first was a nine-year-old who went directly to the left-hand black-key octave as the biggest surprise in a Haydn Minuet in F. A real shocker.
Second was a young man who answered a question about the nature of music composition by improvising his way into several rude surprises of exactly the kind that composers seek to avoid and reacting to them within the improvisation in such a way that I knew he had heard them.
Actual sound is much more vivid than theoretical explanations.