I think the author glossed over the terrible adults in his childhood to make the wrong point. His Dad essentially emotionally abused him over not liking piano

I think the author glossed over the terrible adults in his childhood to make the wrong point. His Dad essentially emotionally abused him over not liking piano lessons and the teacher shamed him for being a quitter. By ripping up the music he showed him by example that being destructive is an acceptable way to respond to challenges and negatives feelings. Nobody stopped to ask him about his feelings on piano lessons. Nobody asked what he didn’t like about them. Nobody asked if he wanted to play different styles of music, try a different instrument, or a different teacher/method of learning. Just punishment and shame. In this context the 1% rule seems more like a coping mechanism for childhood trauma than useful advice.