You're sitting at your desk, eyebrows furrowed, solving a math problem, when your coworker leans over and whispers, "Hey… you good?" You look up confused. "Yeah?" she says, "You just looked really angry." You return to the problem. Thirty seconds later, same coworker: "Seriously though, do you need to talk?" By the time she leaves, you've lost your train of thought *and* acquired the facial expression she was actually worried about.