Being the only one in a coin-op laundromat, when the last people who left, had left it in a disaster.
My guess is that they were homeless people (no ill regard for them), but they left particles of sand, grit, branches, leaves, everything from when they pulled their clothes out of the washer. It was everywhere.
I quietly cleaned all of it up, so the next person to visit the laundromat didn't have to come upon it. It was the right thing to do.