How people dress says a lot about them, even when they don't dress to make a statement. So when Alice walks in wearing all black, chains, Spikes of Villainy, and sundry other signs of violence and villainy, Bob can assume they mean meanness. Except, once Bob actually sits down and talks to Alice, he realizes she is possibly the nicest person he could hope to meet, be she a calm, friendly "Hell's Angel", or an Evil Overlord offering cookies, not to mention the entire Perky Goth trope. Alice may wear Freaky Fashion, but she has a Mild Mind. Antonym to Astonishingly Appropriate Appearance.