What’s the biggest life lesson you’ve summarized so far?

In this world, no matter what field, once you go deep enough into a subject and reach a certain level, you’ll notice an interesting phenomenon.
That is:
In every industry, a group of people who are “half-experts” are always deceiving another group of people who are “complete outsiders.”
And the truly professional “insiders” can’t even get a word in—sometimes they don’t even have the qualification to take the stage.
Not knowing, pretending to know.
Knowing, pretending not to know—and there’s no choice.
This world is made up of a makeshift troupe plus a Ponzi scheme.