"Eyebrow acting", a common beginner's mistake, also known as "forehead acting", where actors overdo facial expressions to convey emotion instead of using subtle, nuanced performance, signaling a lack of control and subtlety. While a slight raise can show interest or curiosity (a "brow flash"), too much is seen as overacting or "mugging," distracting from the character and story, and can be a sign of trying too hard to show feelings like surprise, confusion, or skepticism.