There are vastly more ways for a desk to be messy than tidy, so a desk left alone becomes messy. That is most of it.
The interesting part is that the past being ordered is the thing that needs explaining, not the future being disordered.
I find this oddly motivating: order is not the default, so anything built has to be built on purpose.
Placeholder essay. The real ones will be longer, with the specifics that make them worth reading.