I can always tell when the piano tuner is having a good time. He keeps lapsing into snippets jazz and blues.
It's not wasting time - he'll vamp his way along, then pause, try a note over and over, twang it a bit, and then carry on.
When he actually finishes a whole piece, right up to the final chord, then I know he's done and it is time for me to appear with my cheque book.
So glad that's done then... there were a couple of notes that were setting my teeth on edge.
It's bad enough when the pupils keep playing the wrong notes, but when the right notes are wrong too...