Every man has something like that. Mark Gungor calls it the "nothing" box.
For immediate gratification, jump to 3:17 of this video:
YouTube - Tale of Two Brains
When I was a kid I used to create toys using tools from my father's shop. After being done with a toy plane or a toy battle ship, I play with it for a while. Then I lost interest and I gave them away to a very happy neighbor. When I was a teen my fascination was charcoal painting. I could spend minutes, even an hour, just watching a blank canvass. Once I was done, I gave the painting away. It was someone else's picture anyway.
Others don't understand it. But let me give it my best shot. It's the thrill of pursuing something and then finally getting it that gives us the kick.