Run
Crossing home plate.
What it actually is. A player crossing home plate. The only number on the scoreboard that decides anything.
What a scout reads off it. Runs scored is a team stat wearing an individual's name. It measures the hitter getting on and the hitters behind him doing something about it, which means a leadoff man on a good club will always out-earn a better hitter on a bad one.
How it lies to you. Every serious attempt to measure a hitter, from weighted on-base average to wins above replacement, exists to answer the question runs and RBI only appear to answer.
Batter's Eye: look up anything in baseball