Several years ago, because it was convenient to my office, I used to have my eyebrows waxed at a nearby beauty school. The prices were SO GREAT, and the results were as good as at any spa.
One day I went in and walked up the receptionist:
Me: "Hi. I'm Katherine ... I have an appointment at noon."
Her: "Mustache wax?"
Me: [blank stare] "EYEBROWS."
Her: [looks down at appointment book] "Oh. Sorry. It just says 'wax' in the book."
Me: "Perhaps best not to make the assumption."