A single magpie is considered a sign of bad luck. A Guide to the Scientific Knowledge of Things Familiar recites an old proverb concerning the incidence of bad weather when magpies forage alone and a possible scientific explanation for this.
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Some motorcycle enthusiasts hang a biker's bell from a portion of their bike to protect themselves from evil road spirits.
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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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If one walks underneath an open ladder it is said to bring bad luck. Sometimes it is said that this can be undone by immediately walking backwards back underneath the ladder.
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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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Placing a hat on the bed is, apparently, bad luck. (South Carolina)
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Many believe that if all of the candles on a birthday cake are blown out with one breath, while making a silent wish, the wish will come true.
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It's bad luck to leave a house through a different door than the one used to come into it.
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