In her Tonight Show debut in 2021, comedian Mary Beth Barone defined certain types of people that she should not “legally” be allowed to date. On the list: marathoners, men who considered The Beatles their favorite band, and guys who had navy sheets with one pillow. “Where were you then, Federal Government?” she lamented.

Barone’s bit touched on a certain anecdotal—though perhaps not totally unfounded—truth: bachelors love blue sheets. “I designed about 400 apartments in New York City when I lived there and most were for bachelors,” says Kiel Wuellner, a senior creative director at Vesta Home, a luxury home staging company. “And they all had blue or gray sheets.” The joke isn’t just that it’s a frequent motif in single men’s homes, but rather, a red flag.…