What should we do, then, when we are pressed by the powers that be, by our colleagues, or even our kids to start "acting like adults".
Press them to define "adult".
Much of the time, they will either be flummoxed to provide a positive answer. If they sputter nothing but negatives, tell them to stop evading the question. If they say that an adult acts like so-and-so, press them to explain what qualities exhibited by that person add up to "adulthood."
Responsibility is not enough. Children have to take on responsibilities at home, just as older people have jobs and families to attend to.
If it has to do with knowledge, simply acknowledge that there are many smart people who cannot take care of themselves, who make no effort to care for the needs of others, or who refuse to make sense of their place in the world/
In all likelihood, most people throw out the charge of "act like an adult" to shame the freedom in which an older person chooses to demonstrate in their lives, regardless of the scolding or shame that he or she may face. In other cases, most people so despite not receiving immediate agreement or validation that they slam the purposed obstinacy of others as "childish".
Yet we should not allow the petty frustrations of others dissuade us from doing what is right.