"The only remedy is for all to sit or stand together, or for one or more of the party to be seated at another table.
Equally ubiquitious is the fear that a Friday, itself an unlucky day, that falls on the thirteenth day of the month is a day when anything that can go wrong will go wrong. Even in modern technologically advanced society, business will fall off whenever a 'Friday the thirteenth' comes round as important deals are delayed until a more propitious date. New undertakings of many other kinds, including weddings and other events of a personal nature, will also be postponed.
In reality, the prejudice against the number thirteen is of obscure origins, as evidence exists of it in Roman civilisation long before Christ and the Last Supper, which is none the less usually cited as the source of the superstition.
Perhaps significantly, the number thirteen was to ancient Egyptians the last step of the ladder via which the soul reaches eternity, though other authorities gave suggested Hindu origins."