It is the power of color that makes the world happy.
Skating over landscapes full of dashing blues, brilliant yellows, charming greens... what more could a unicorn want? Arcoiris loved color, and he loved being the world's artist.
For a very long time, he had been able to use his long tail to add a sparkle of color to the hills he lived in. With his spectrum powers, given to him from the rainbows themselves, he felt overwhelming joy at his ability to paint the world with vibrancy and hope. For what makes others happier than seeing cheerful flowers in purples and reds and oranges?
Underneath the skies of smiling clouds, he would run with his friends. Arcoiris loved it when their faces would light up with marvel and delight. "Look at the bold colors on that tulip! Only Arcoiris could have made something so beautiful."
As time wore on, though, the colors faded from his tail, and he found that he could no longer paint. The hills he lived in, while nice, lost the brilliance that had once made the place the envy of the world. Why, even the grass seemed dimmer than it once had been, and Arcoiris's friends noticed. Their faces would no longer light up with the same delight when they ran around the hills. Everything just seemed so... so normal.
Down at a river tucked between the hills, Arcoiris mulled over this problem. Without his ability, the world no longer looked so colorful and happy. What could he do to bring surprise and delight to others once again?
He kicked an orange hoof down at the ground in frustration and noticed a small pile of rainbow jellybeans that a child must have dropped. The world still has color, he thought. I just need to find a new way to paint with it!
The winking sun turned so that it was just a little more north, because it wanted to get a better view of Arcoiris's home. Inside his dwelling in those charming hills, the unicorn had found a way to be an artist again. The home spilled over with colorful food, stickers, clothes, and trinkets. The wide array of colors and the effervescence of the objects attracted the attention of all of the local residents.
Arcoiris would throw his doors open each morning and welcomed all who wanted to come marvel at his collection. Being able to hear their happy tones as they spoke in awed voices made him hum with happiness. He had found a way to paint again.
And what makes the world happier than color?