I remember, about 20 years ago, a student, in their mediocrity, explaining to my teacher that they hadn't practised during the week because they didn't want to practise it wrong. My teacher's reply was: Never let high standards prevent you from practising. This instruction deservedly became a catchphrase, and I still use it all the time in my own work, especially, since not practising is no longer an option, in the rephrasing: Never let high standards get you down; or even: Never let let high ideals turn you into a victim.