Failure should be a part of learning and we should learn to embrace failure. My poster child example of this is tracking falling down when ice skating / skiing

Failure should be a part of learning and we should learn to embrace failure. My poster child example of this is tracking falling down when ice skating / skiing. Not falling is a poor metric of success as you see many people not fall but are also clearly not ice skating. Falling is to some extent a metric of how hard you are pushing yourself. With instruments, practising mistakes can be costly because establishing muscle memory is habit formation and baking in mistakes is essentially inefficient in your time spent learning. As my teacher would say "practise like you are up on the stage in front of thousands. Perform like you are alone at home in your pyjamas." Don't be afraid to make mistakes, but always practise smart. (FWIW I spent the best part of 15+ years NOT practising smart)