(n.) A disposition in which someone meets a situation with exactly the attention it warrants — neither under- nor over-invested — having arrived there by first passing through a phase of excessive attention rather than by skipping it. Plain-English gloss: “second ease,” to distinguish it from the first, naive ease of simply not knowing better.
Eumetric reciprocity (n.) — the social equilibrium that holds only when both parties in an interaction maintain a eumetric disposition; it breaks down if one party over- or under-invests relative to the other.
Related: The 10,000-hour rule of mastery · Do one thing with complete attention