Think for a moment about your hands and their habits. It's hard not to take hands for granted as they are so habit driven. This is probably even more the case for pianists than for any other instrumentalists because the piano invites the pursuit of efficiency.
But consider this: The sound of the piano is incredibly complex and all sound is infinitely variable. Everything affects the way your instrument sounds, even who is listening. Your fingertip is your connection to the myriad details of the sound--your finger may touch the key but the fingertip gives access to the subtle colors emanating from the strings.
Give your hands a break. Take something into your hand that you haven't thought about recently: a few pebbles from a planter, a leaf or some grasses perhaps. Close your eyes and let your fingertips explore as if they are your eyes.
Next time you play let your fingertips become your ears.