We've all slammed head-long into this scenario: we need to learn how to do something, and by asking, we are told, usually condescendingly, that everyone knows how to do it, and RT(F)M and LMGTFY. Yet, when we look it up, no one has ever written up a guide because "everyone knows how to do that."
So, we eventually just hack and stumble our way through the non-obvious stuff, feeling like idiots for not being born with this innate knowledge that everyone else seems to have.
And then, as we achieve that knowledge, we realize, the "everyone knows" is just imposter-syndrome-driven smokescreening.
So, let's help cut the cycle here! What is ONE thing in computer programming or IT that is generally considered obvious, but actually isn't? What do you wish someone would have told you about that subject back when you learned it?