Karl went to the store to buy a set of tools to fix his car. Only when he got home did he discover that all of the wrenches were SAE instead of metric. Discouraged, he walked back toward the store.
On the way Karl stopped, deep in thought. But while he stood there the freshly poured concrete of the sidewalk set, and Karl lost his best pair of shoes. Demoralized, he turned back home in his socks.
But Karl got lost in the dark, because the sun had already set. And for all we know he still wanders lost, in his stockinged feet, carrying the wrong set of tools.