There are numerous sailors' superstitions, such as: it is considered bad luck for a ship to set sail on a Friday, to bring anything blue aboard, to stick a knife into the deck, to leave a hatch cover upside-down, to say "pig", or to eat walnuts aboard.
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Once a wedding ring has been placed on the finger, it is considered bad luck to remove it.
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Placing a hat on the bed is, apparently, bad luck. (South Carolina)
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At times, a horseshoe may be found above doorways. When positioned like a regular 'U' it supposedly collects luck. However, when it is positioned like an upside-down 'U' the luck supposedly drains.
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Opening an umbrella indoors is said to result in 21 days of bad luck. Some traditions hold that it is only bad luck if the umbrella is placed over the head of someone while indoors.
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Two people breaking a wishbone is said to lead to good luck for the person with the larger piece.
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An acorn should be carried to bring luck and ensure a long life.
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Placing keys on a table is considered unlucky. (Sweden)
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