No matter how modern or enlightened we might consider ourselves—and our society—to be, superstition lingers. Just check out some buildings with floors that go into the teens or higher—is there a 13^th floor? An estimated 85% of U.S. buildings with more than 13 floors actually skip that number.

Those of us who knock on wood, throw salt over our left shoulder, and avoid walking under ladders likely do so because of tradition—and hey, most of us need all the good luck we can get, right? If you’re...