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
Placing keys on a table is considered unlucky. (Sweden)
3
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
It's bad luck to leave a house through a different door than the one used to come into it.
143
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
An acorn should be carried to bring luck and ensure a long life.
115
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.
75