I have shoes. My friend has shoes. I suspect you have shoes, too.
That one time someone broke into my friend’s house, but later the investigator found a footprint. Long story short, this footprint ended up leading him to the culprit and he put him behind bars. The investigator did a great job, we all applauded him. Little did we know this case set a precedent and exactly one year later a new regulation came into action: every pair of shoes must have a unique footprint and you have to provide an ID whenever you buy new shoes.
With this the World has changed and crime disappeared.