A park’s worn grass shows where people actually wanted to walk.

Behaviour leaves a record that intentions do not. The path was drawn by a planner and the line across the grass was drawn by everybody, and where the two disagree the grass is telling the truth about what people need. It is honest data, unprompted and free, and usually treated as damage rather than feedback. Use argues with design eventually.

Look for the worn line in something you are responsible for: the workaround people use, the form field everyone skips, the door nobody enters by. Rather than fencing it off, ask what it is telling you. Often the answer is to pave it.