In “Killer Instinct” Rafael Corrales writes:
There are no plus-minus stats to measure a player’s ruthlessness, his desire to beat his opponent so badly he’ll need therapy to recover. [...]
Athletic greats squeeze every ounce out of their abilities. That drive and hunger is worth noting, since top athletes are typically not satisfied even when pulling in accolades, championships, and money.
Instead of measuring success relative to the general population, or a peer group, the great ones measure success relative to their potential and abilities.