Being able to share pop culture references can be a sign of true friendship. It means you both appreciate the same things and have a similar sense of humor.
Recently, when a man on Reddit was grief stricken over his grandmother dying, his friend asked him if there was anything he could do to make him feel better. In response, the Redditor jokingly said, "A single plum, floating in perfume, in a man's hat," a reference to 'The Simpsons' episode 'Homer's Barbershop Quartet.' A famous scene in the episode, which parodies The Beatles, features Barney Gumble's Yoko Ono-esque girlfriend ordering the bizarre concoction at Moe's Tavern.