You think everyone clocked your bad outfit. Almost nobody did.

Researchers had a student wear a T-shirt with an embarrassing image into a room of strangers, then asked the wearer to guess what fraction of people had noticed it. Wearers guessed roughly twice the actual number who noticed. We're so aware of our own appearance and blunders that we assume everyone else is watching just as closely — they're not.

— Thomas Gilovich, Victoria Husted Medvec, and Kenneth Savitsky, The Spotlight Effect in Social Judgment: An Egocentric Bias in Estimates of the Salience of One's Own Actions and Appearance — Journal of Personality and Social Psychology, 2000