The hide and seek heart.

It's nearly the end of spring in Black Forest, Britain. A group of young campers disperses in the woods, slowly getting swallowed by the long trees.  Patches of shy-looking sunlight razorcut through the green carpets of their leaves. Ah, those green carpets! Under them they ran, and hid, and seeked for endless hours. Like there was no tomorrow.

I would very much like to know why people stop playing this game when they grow older.