3 ideas
A musician cannot move the listener unless they are themselves moved, so the player must enter each affect the music expresses, becoming languid in sad passages and fiery in lively ones. Emotion is transmitted by contagion from performer to audience, which means technical accuracy without felt engagement produces sound that leaves the hearer cold.
Good fingering is chosen by looking ahead to the notes that follow, so the hand arrives prepared rather than cornered, with the thumb passing under and the fingers crossing over to keep a line unbroken. Because a finite set of fingering patterns governs all keys, mastering the principles transfers to unseen passages, while ad hoc fingering forces awkward shifts that break legato and distort the phrase.
Trills, appoggiaturas, turns and mordents are treated as structural elements that link notes, supply emphasis and carry affect, not as optional surface embellishment. Each ornament has an exact placement and execution tied to its harmonic function: an appoggiatura, for example, takes its time from the main note and so creates a dissonance that resolves. Overused or misplaced ornaments corrupt a piece the way excessive spice ruins food.