A 2011 study found that Chinese consumers are charged more due to “superstitious manipulations” of retail prices—fives and sixes appear more often than unlucky fours, eights and nines more than unlucky sevens. “Retailers,” the study reported, “are the clear winners.”

It’s considered bad luck in parts of Mississippi for mourners to call a coffin pretty.

When Booker T. Washington and Austrian ambassador Ladislaus Hengelmüller visited the White House on the same day in November 1905, Hengelmüller took Washington’s overcoat by mistake. According to the Washington Post, he noticed the mix-up on finding in the pocket “the left hind foot of a graveyard rabbit, killed in the dark of the moon,” which he “heroically relinquished.”

In July 2003 details leaked of a new venture from the Defense Advanced Research Projects Agency: an online market for financial speculation on possible terrorist attacks, assassinations, and coups. “Futures markets have proven themselves to be good at predicting such things as elections results,” the Defense Department argued. “They are often better than expert opinions.” DARPA—already under fire for its proposed Total Information Awareness program—was forced to abandon the idea.

When Apple released its Shuffle feature for iPods, users were deceived by the true randomness of its playback; songs from the same album or artist were often grouped by chance. Complaints led Steve Jobs to alter the device’s programming and begin offering Smart Shuffle, which allowed users to adjust the likelihood of hearing similar songs in a row. “We’re making it less random,” he said, “to make it feel more random.”

Legend regarding the horseshoe as a lucky symbol holds that in the tenth century, while St. Dunstan was working in England as a farrier, the devil entered the forge and demanded his hooves be reshod. During the process, the future saint caused as much pain as he could, and the devil begged him to stop. Dunstan agreed—on the condition that Satan never enter a house where a horseshoe is on display.