Naive realism suggests an answer: they do. It calls to mind a famous line of George Carlin’s: “Have you ever noticed that everyone driving slower than you is an idiot, and anyone going faster is a maniac?”
Whitchurch and Epley took photos of people and blended their facial image, in 10% increments with either an attractive or unattractive face. So the face became more or less attractive. We then showed people all 11 versions of their faces – their actual face, the 5 blended with the highly attractive face, and the five blended with the highly unattractive face—in a randomly ordered lineup and asked them to identify which face was their own. We found that people tended to select attractively enhanced images of themselves, thinking they were more attractive than they actually were.