This was a new one on me, never heard of it. "There is a folklore superstition regarding the giving of a knife as a gift. If the knife is given to a friend, money must be exchanged as well. It is considered very bad luck to give someone a knife without exchanging money or the friendship will be cut by the knife. Because of this superstition, it is common that the gift of a knife will be given along with a penny, nickel or dime in the box with the knife so that the recipient can give back the coin, thereby saving the friendship from being severed by the giving of the sharp blade. The exact background of this superstition is unclear yet; even today most people will include a coin with the gift of a knife and request the coin be given back. The apparent view is that it is far better to be safe than sorry." Do you know of any odd superstitions?