And not just because you'll poke someone's eye out. Opening an umbrella indoors is supposed to bring bad luck, though the origins of this belief are murky. Legends abound, from a story of an ancient Roman woman who happened to have opened her umbrella moments before her house collapsed, to the tale of a British prince who accepted two umbrellas from a visiting king and died within months. Like the "don't walk under a ladder" superstition, this seems to be a case of a myth arising to keep people from doing something that is slightly dangerous in the first place.