I think the following equation describes pretty well the process of learning a new piece or solving a difficult passage in a piece:
T = D/P
- T is the time it takes learning the piece or passage
- D is the objective difficulty of the piece or passage
- P is the patience we have to solve things.
So, when difficulty is bigger and patience is the same, learning takes more time. When difficulty is the same and patience is bigger, it takes less time.
When P tends to zero, learning time tends to infinite (I am sure the colleagues who teach beginners will have a story or two about this). When patience tends to infinite, time tends to zero (this is called “perfect sightreading at black-belt mastery level”).
Our level of patience will naturally vary according to the moment, the mood, the concentration, the love you feel for the piece you are learning, the love you have for yourself, the time you have. But it would be interesting to try once, independently of objective conditions, to practice as if we had infinite love for the piece we are learning, infinite forgiveness for oneself, infinite time. Just "as if", just to see what happens.