Play reminds adults that usefulness is not the only justification for doing something.

Somewhere in becoming an adult, doing something for no reason starts to feel indefensible. Play is the direct contradiction of that: activity with no output, no improvement, no justification. Its pointlessness is not a weakness in the argument for it, it is the entire content.

Do something this week that produces nothing. A game, messing about with an instrument, building something useless. Resist the urge to make it into a project or a skill. The value evaporates the moment it acquires a purpose.