[U]nless you’re extremely organized, a house full of stuff can be very depressing. A cluttered room saps one’s spirits. One reason, obviously, is that there’s less room for people in a room full of stuff. But there’s more going on than that. I think humans constantly scan their environment to build a mental model of what’s around them. And the harder a scene is to parse, the less energy you have left for conscious thoughts. A cluttered room is literally exhausting.

Paul Graham, ‘Stuff’, July 2007