I think I need this quote in my kitchen! My girlfriend often pounces be with the accusation "YOU'RE NOT WORKING" if she sees me out of my chair moving around, doing mindless house chores or half-vacantly tossing a cat toy around the house, or running errands, but the reality of _design_ is that it happens all day. And when you're done 'work' for the day, ideas and solutions still happen.
I'm working in the shower, I'm working all evening. I'm working waiting for the bus. I can either let it pass or write it down, but I can't seem to shut it off.
But I don't mind. I've been learning to slow down too. I used to be a perfectionist and when I was billing a client I would only bill my butt-in-chair-and-head-down time as billable hours, but lately I realize if I sit and think, plan, and research for 2-4 hours, and spend 2-4 hours implementing the results of that thinking, I get more done each day than 8 hours of butt-in-chair-head-down typing.
They key is to approach it as design, and that's where my training as a graphic designer comes in handy. The Design Process was drilled into out heads and I've only recently been applying it to my coding :)