Shabbat 60 - Sandals
A man may not go outside on Shabbat wearing a hobnailed sandal, which is a sandal with short nails (hobnails) used to increase its durability and to connect the shoe's upper to the sole. This is prohibited because of the following incident.
Once, in the times of Roman persecution, people were hiding on Shabbat in a cave. They made a rule: anybody can come in, but nobody can leave. One person came in a sandal that became reversed (this sandal could be worn from both ends), and people mistakenly thought that someone has gone to denounce them. In the ensuing panic people pushed and kicked, and they killed more of each other than did the enemy. To prevent people from remembering this sad incident, the Sage forbade wearing such shoes on Shabbat. - But if so, let these shoes be forbidden altogether!? - The prohibition was only in circumstances similar to the incident.
Some relate a story where the people hiding in a case heard a noise, some say that they were hiding in a synagogue, and some say that all three incidents actually happened. However, multiple variants of hobnailed shoes are allowed: those that are made for ornamental purposes (as evidenced by fewer of the nails being used), and those whose hobnails have worn out and are now level with the sole.
Art: Vincent Van Gogh - Three Pairs Of Shoes