The tree

There once was a forest of trees. In the midst of all the trees was a singular tree. There was nothing remarkable about the tree that would call it to your attention, for it was the same size, color, and shape as all the other trees. It grew the same way, had just as many bird's nests in its branches, gave off the same amount of oxygen as every other tree in the forest.
The forest grew taller and wider, soaking up sunshine and soaking in rain. The noted tree grew with it, without complaint. Soaking in the rain and shine like all the others, for years and years.
But one day, the tree had a thought.

I am tired of growing.

I am big enough.

So it stopped growing. It shook of the raindrops when they came down. It exhaled the sunshine. 

For a while, the tree thought it was nice not to expend energy on just growing bigger. The tree relaxed and spent its time resting and enjoying itself.

Years passed and for a long time all was well.

But the little tree seemed to shrink under the branches of its fellows who were still using their sunbeams and raindrops to grow tall. 

Soon enough, the little tree was dwarfed by the forest. It could no longer see the sky; the rain no longer spattered on its face. It was no longer warmed by the beams of the sun. 

The little tree shriveled up and rotted in the shade of his healthy friends. It became hollow and fell with a crash to the forest floor. The remains of the tree turned to waste and fertilized the roots of his old friends and fed the mouths of the forest creatures. 

The End

The moral of this story is to never stop improving yourself and never stop growing.