The "Rate Your Pain" scale, interpreted in an infographic.
This has obvious application to illness and injury in modern-day settings; it may also be of real-life use to people who (like me) tend to be flummoxed by That Question: compared to what? On the scale of all the pain I've ever suffered? When I move it like this? Compared to that guy in the next waiting-room seat stoically nursing a hastily-bandaged stump?