Tony Perez's Art of War: When a drinking glass accidentally breaks, do not replace it immediately. Just let it be, especially if you have other glasses in reserve.

An accidentally broken drinking glass saves you from others wishing ill on you. If you replace it immediately with a new one, they will continue to wish ill on you all over again.

Gather the broken pieces and smallest shards in a plastic bag, write your enemy's name/enemies' names on a sheet of paper, place it inside the bag, and throw the bag in a public trash bin.

The ill wishes sent you will immediately redound on the sender/senders.