The days you play badly still count. Your hands learn even when your ears are disappointed.

Progress and the feeling of progress are two different things. On a rough day your ears catch every ragged edge while your hands are quietly learning the shape of the thing anyway, and that learning does not require you to enjoy it. Judging a session by how it sounded throws away most of what you did. The ordinary gains tend to hide in the bad days.

Count practice by whether it happened rather than by how it felt. Write the date down and skip the review. Come back tomorrow and let your hands show you what they kept.