Many manager types are good at faking it, others are genuine hypomaniacs or hyperthymics (see https://en.m.wikipedia.org/wiki/Hyperthymic_temperament ), and others still are systematically taking stimulants, prescribed or not. And then there are extroverts and introverts.

There is little doubt it is biological, it's just that this aspect of natural biological diversity is poorly studied.

Nature would lend itself to more mutability, if only people decided to drop the pretense that "attitude" is the only differentiator. It is not.