Walk around parks or college campuses and there, amid the neat sidewalks and pathways, you will find messy trails of people, worn-down dirt paths through the lawns, grasses, and even flowerbeds. The trails are social signifiers, a clear indication that people’s desires do not match the vision of the planners. People try to simplify the paths they take when walking, taking short routes rather than long ones, even if it means walking across gardens or scampering up hills.
Landscape architects and urban planners are not pleased with the resulting destruction of their grounds. Some planners resent them, treating them as a destruction by thoughtless, lazy people of carefully laid-out plans. These human-made trails are called “desire lines,” for they reflect desired paths even though the formal layout of streets and sidewalks do not accommodate them. Wise urban planners should listen to the message underlying these desire lines. When a desire line destroys the pristine plan, it is a sign that the design did not meet human needs.
Don Norman, Living with Complexity, p. 126