Learning an instrument teaches you that “can’t” is often just “haven’t practiced this part slowly yet.”

An instrument gives you unusually honest feedback. A passage you cannot play is not a mystery about your ability; it is a specific sequence your hands have not yet done slowly enough, enough times. Once you have felt an impossible bar turn into an easy one, it gets hard to take that word at face value anywhere else.

Take the hardest four seconds of whatever you are working on and play it at half speed, ten times, cleanly. Only speed up when nothing is sloppy. Then notice where else you have been saying you cannot do something you have not yet tried slowly.