When you speak of bad luck, it is said that one should always knock on wood. Also knocking when speaking of good luck apparently helps with having good luck. This is an old Celtic tradition related to belief of wood spirits.
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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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Placing a hat on the bed is, apparently, bad luck. (South Carolina)
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Placing keys on a table is considered unlucky. (Sweden)
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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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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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Collect seven or nine different flowers on midsummer eve and place them under your pillow and it is said that you will dream of your future spouse. (Sweden)
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If you catch a falling leaf on the first day of autumn you will not catch a cold all winter.
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