This really happened to a self-depracating friend of mine
My wife and I were browsing in a crafts store when I noticed
a display of country-style musical instruments. After
looking over the flutes, dulcimers and recorders, I picked
up a shiny, one-stringed instrument I took to be a mouth
harp. I put it to my lips and, much to the amusement of
other shoppers, twanged a few notes on it.
After watching from a distance, my wife came up and
whispered in my ear, "I hate to tell you this, honey, but
you're trying to play a cheese slicer."