The Illusion of Transparency
You think your nerves are written all over your face. They're not.
Grounded in the research on illusion of transparency
Notice when you assume they know
The illusion of transparency is the tendency to overestimate how visible your internal states — anxiety, boredom, attraction, guilt — are to other people. You feel it intensely, so you assume they see it. They don't. Your inner experience leaks far less than it feels like. This is distinct from lying or hiding; it applies even when you're making zero deliberate effort to conceal anything.
Know the actual study
Thomas Gilovich, Kenneth Savitsky, and Victoria Husted Medvec named and tested this at Cornell in 1998. In one experiment, people who were nervously lying in a trivia game consistently predicted observers would detect their lies at high rates. Observers couldn't. In another, people faking that a drink tasted bad thought they were obviously betraying disgust. Judges rated them as perfectly composed. The data is clean: you wildly overestimate your own legibility.