There was a time—remember that time?—when you missed out on something important. You didn't achieve what you wanted, or you tried to do something that didn't work out. The experience stung, but you forgot about It and moved on. Or maybe you resolved to fix It right away, and did. Or maybe you put It away (It was only a little black speck of a thing anyway), giving It a little space.
It was an annoyance, but It resided in the back of your mind, that little speck, with your other neglected memories, long-solved problems, and discarded plans.
For some of you, It was content back there, along for a ride, not causing you many problems. But for the rest of you, It morphed; no longer a simple annoyance, It began to take up more than its fair share of space, intruding on the rest of your life, becoming untenable, a hostile invader.
At some point, It demanded action. With so much time gone by, satisfying It was no easy matter. It demanded tenacity, even a bit of cleverness. But you'd been around long enough to know that you could take care of It. And you did. When you had finished It, you were amazed at how brightly It shone; It gleamed in the sun, catching the light just so.
After all your friends congratulated you on your accomplishment, It took up residence in that space that had been waiting for It. It could't begin to fill up all the space you had created for It.
But It was content, and as time went by, It grew: not too much, certainly not out of proportion to its importance, but filling out that empty space quite nicely. And even better, that ungainly space—with time and inattention—receded, until It and that space were one, inseparable and satisfying.
Happiness is the color orange.