"People often think of play as frivolous or trivial, and they are right. As I have explained, play is activity conducted for its own sake rather than to achieve serious real-world goals such as food, money, praise, escape from a tiger, or an addition to one’s résumé. It is activity that takes place at least partly in a fantasy world. So it is indeed trivial! But here is the most delicious of play’s paradoxes: the enormous educative power of play lies in its triviality."

"Play serves the serious purpose of education, but the player is not deliberately educating himself or herself. The player is playing for fun; education is a by-product. If the player were playing for a serious purpose, it would no longer be play and much of the educative power would be lost."

"Fear and concerns about evaluation tend to freeze the mind and body into rigid frames, suitable for carrying out well-learned habitual activities but not for learning or thinking about anything new. In the absence of concern about failure and others’ judgments, children at play can devote all their attention to the skills at which they are playing."

"A playful activity that becomes too easy loses its attraction and ceases to be play."

Peter Gray - Free to Learn