While the origin of this superstition is unknown, one version says putting new, unused shoes on a table is bad luck because new shoes were traditionally put on the dead while they laid on a table. Therefore, putting new shoes on the table could bring about bad luck or death.
Another reason it is bad luck to put shoes on a table is that used shoes can cause unsanitary conditions. Used shoes should not be near food or any areas where food is eaten, so placing shoes on a table in general is bad luck. Some people believe throwing shoes at a person leaving home gives them good luck.