A demonstration succeeds when the observer can see the decision inside the movement.

Watching someone do a thing well teaches almost nothing when all you can see is the result. The useful part is the choice being made: why the hand went there, what they were checking, the point where they slowed because something could go wrong. Skilled people perform those decisions so smoothly that they vanish into the motion. A good demonstration deliberately slows down and puts them back on show.

When you show somebody how to do something, narrate the choice rather than the action. And when you are learning, ask what the person was deciding at the moment you cannot reproduce.