There was once a forest made up of tiny trees that were all growing up together. They had been planted by a very old labourer who took care that they would all grow up to be straight and healthy. However, the area was battered by strong winds, and the little trees preferred to avoid the bothersome gusts, so they bent their trunks and branches to shelter themselves. The old man, knowing they could never grow well like this, set about straightening them out, and spent many hours tying their slim trunks to supporting posts, hoping his beloved trees would understand he was doing this for their own good. But those naughty trees had no desire to put up with all that wind. It mattered not to them that the old man would promise them that when they were tall and upright the air wouldn't bother them a jot. They always got by by bending and twisting themselves, hiding from the wind. Only one of those trees, one located right in the middle of the forest, forced itself to grow up straight, patiently bearing the annoying gusts. The years passed, and the old man died. And from then on the trees could grow however they liked, bending and crouching from the wind just as they pleased, with no one bothering them about it. All, that is, except the single straight tree in the centre of the forest, who remained determined to grow up just as a tree should. But as the forest grew, and the trees got thicker and stronger, they began to hear cracks from inside. Their branches and trunks needed to keep growing, but the trees were so twisted that the inexorable growth they were experiencing only brought them pain and suffering, even more than the suffering they had avoided by staying out of the wind. Each day and night, in the depths of the forest, one could hear the cracking and snapping of the trees, and it sounded like groans and sobbing. And around that area the place became known as the wailing forest. And it was a place with a special charm since, right in its centre, surrounded by thousands of short, knotty, twisted trees, rose one impressive tree that was long and straight like no other. And that tree, the only one that never creaked or cracked, continued growing and growing, without a worry for the capricious wind and its accomplice, the breeze. 
A metaphor about good posture for children, looking at possible future consequences of too much comfort. 