One other problem is that whenever these conversations come up in "extremely public spaces" (i.e. the internet), you inevitably have a small group that strongly identifies with the textbook definitions of introvert/extrovert. Anecdotally (though this is the internet), this is almost entirely self-identified introverts; they will swear that every social interaction leaves them drained and they need a certain amount of hours alone to recover (there is almost certainly some confounding variables and bias at play here). Afterwards, those that do not see their own lives described by these definitions are generally less interested than the former group in arguing about the definitions' supposed validity.