Energy
The definition we tell ourselves of Introvert is “I do not like being around people”. And an Extravert is self-defined as “I do like being around people”.
Maybe a deeper explanation is warranted. Introverts have their energy drained by being around other people. And it's replenished by solitude.
Extraverts have their energy replenished by being around other people. Their energy is drained in solitude.
Digging even deeper, this energy expenditure and replenishment can vary based on the kinds of people one is around. Friends, family, your chess club, open office cube space. Working from home, alone.
Have you considered how your energy is expended and replenished with the lens of the different kinds of groups you participate in?