It's bad luck to leave a house through a different door than the one used to come into it.
143
The superstitious symbolism of a black cat crossing one's path is dependent upon culture: some cultures consider this a sign of impending bad luck, while some cultures consider this a sign of impending good luck.
75
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.
49
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.
298
Placing a hat on the bed is, apparently, bad luck. (South Carolina)
9
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.
105
Before traveling a person should, apparently, sit on their luggage. (Russian)
117
An acorn should be carried to bring luck and ensure a long life.
115