Here's a story I've heard; I wouldn't be surprised if it's apocryphal, but it still made me think.

A janitor at the Louvre overheard some people who were looking at the Mona Lisa and discussing it critically. He was put out of patience by their discussion and said to them: "You can't judge the Mona Lisa. It's a classic; its place in Art is established. When you come to the Mona Lisa, it's you who are judged, by your reaction to it."

Marion