There is something magical about creating something.  It makes your soul grow, and life richer.
Snatching an idea out of the ether, letting it percolate in your brain for a bit, and then giving it form is extremely gratifying.  You're turning something ethereal into something physical and substantive.

I think this is why I like programming--the ability to take an idea and make it real has always appealed to me.  It's the same reason why I love to paint, make music, and write.  I find that many programmers are the same way, just inherently creative people.  Many programmers I know also play musical instruments.  I assume designing a house, building a car, or paving a road give the same kind of satisfaction, but I'm just guessing there.

Somehow the very act of creating expands your mind and opens up new possibilities.  Whenever I'm doing something creative it attracts new ideas and gives me more energy than two pots of coffee spiked with Red Bull.  I get more new and random ideas while I'm creating something--writing, painting, programming--than at any other time, along with the energy to work on them.

On the flip side, doing things that are not at all creative seems to sap my energy.  This is why I hate debugging and administrivia.  It sucks the life out of me.  I feel like a button-pushing zombie.

Of course I guess that would make people that don't create anything but simply leach off of productive value created by others soulless monsters.  People like the financial engineers who repackaged and obfuscated risk and poisoned our economy--leaches.  The lobbyists spending their days and nights working hard on conning our tax money out of Washington--soulless.  I think that sounds about right.