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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Breaking a mirror is said to bring bad luck for 7 years. To "undo" this, take the shards of glass and bury them underneath the moonlight. In ancient times, the mirror was said to be a window to the viewer's soul. If that mirror were to break, it would
123
It's bad luck to leave a house through a different door than the one used to come into it.
143
Some motorcycle enthusiasts hang a biker's bell from a portion of their bike to protect themselves from evil road spirits.
64
Before traveling a person should, apparently, sit on their luggage. (Russian)
117
Placing keys on a table is considered unlucky. (Sweden)
3
Once a wedding ring has been placed on the finger, it is considered bad luck to remove it.
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It is bad luck to put new shoes on a bed (or a table) (comes from the tradition of dressing a corpse in new clothes and shoes and laying them out so everyone can give their respects) - (UK)
57