|When presented with a space like this, I absolutely|
will walk straight through the middle rather than around.
When you walk everywhere, following desire lines is
as much a matter of conservation of energy as it is
convenience. Source: sugoru.com.
Of course, as has often been pointed out, sometimes the users are wrong. And sometimes so many desire lines pop up that it would be silly to officially legitimize all of them. Cities have to strike a balance--neither chasing after every desire line nor categorically ignoring them all is the correct answer.
One of the most interesting conclusions from Mr. Colville-Anderson's research is that when adequate and safe infrastructure is provided for people who ride bikes, then the actions that people on bikes take to keep ourselves alive and safely moving from point A to point B on infrastructure not designed for us--actions drivers frequently resent and complain loudly about, all while doing nothing to make people on bikes safer--those actions go away when infrastructure is adequate. When each road user had sufficient space and room to breathe without having to carve our own desire lines, positive interactions from all is the result.
I ran across a great statement in the book Shakespeare's London On 5 Groats a Day: "In England, roads are not made--they happen, whenever a sufficient number of people and horses tread out a track to wherever they wish to go." Many of these original desire lines across not only England, but also Europe, and indeed across the parts of the US where most roads predate automobiles, have been codified into the road system now. Desire lines are a life hack spread across entire cities, showing the real ways humans interact with their environment.