In the dream I tuned a piano that had no strings

I'm turning the tuning hammer, and the pins turn smoothly, but there's nothing attached — just the bare pinblock and a room full of patient people waiting for the first note. I keep checking my ears, thinking maybe I've gone deaf, but I can hear everyone breathing. Then I notice the sheet music is a list of names, all customers I've lost track of over the years, and I wake up feeling like I owe someone an apology.