Observation
Specialists know what amateurs cannot see.
Michael Rejent, an air traffic controller, catches mistakes with a glance out the window that radar misses. He sequences departures like a moving puzzle, scrambles when a jet takes off without clearance, and knows which phrase makes every controller in the cab look up. This is what actual expertise looks like: it operates in the space between what systems measure and what humans perceive. We live in an age of instruments and interfaces, yet the person who stops a disaster is still the one paying attention.