The longer you sit at the table, the more you start to suspect the truth. The cards are not the lesson. The opponents are not the lesson. Even the money, after a while, is not the lesson.
The game has been teaching you, hand after hand, year after year, in a language you didn't know you were learning. Showing you, with perfect indifference, who you actually are when the chips are in the middle. When the bad beat hits. When the cooler comes. When the bluff works. When it doesn't.
There is no other practice in modern life this honest.