In my dayjob, if my work-space gets cluttered, my brain gets cluttered, too. I seem to have to file stuff and straighten things, or I can't think straight.
At home, my art-table creates the opposite effect. If I tidy it up, I can't work well. My brain starts trying to follow the rules, and my ideas get all tight and well-behaved, and it takes me a long time to realize that they've led me down the wrong path.
This jumble of odd-sized paper, weird brushes and crummy pens seems to say, "There's nothing to lose, and God knows there are plenty of us, so just get in here and play around." It's a good place for messing around and making a lot of mistakes. Once in a while, a good idea pops out.
And there's a big old bin underneath the table, for catching the clunkers.