This post is going to ruin part of your life. I'm warning you, here at the outset, that you won't be able to unthink this idea. This is arrow-in-the-FedEx-logo stuff.
Every day you hear a reference to The Wizard of Oz. Every day! I cannot find the origin of this theory, but I was introduced to it in 2001. (Is this the most significant thing I learned in college? We may never know.) Since then, I feel a little ding in my heart whenever that day's reference comes up. A few days ago, it was a co-worker using the phrase "I'll miss you most of all." When it's windy, you are likely to hear some goober say, "It's a twister, Auntie Em!" But sometimes it's a horse of a different color, because you're paying no attention to the man behind the curtain since we're not in Kansas anymore, and I'm melting, I'm melting, and there's no place like home, and I'll get you my pretty — and your little dog, too, because ding-dong, the witch is dead. Watch out for the lions and tigers and bears, oh my. (This comes up constantly in headlines. Keep your eyes peeled.)
Yes, this is often just confirmation bias — we don't notice days where there are no references made, and surely there are other popular works that are frequently referenced or alluded to. But few of those allusions both retain a strong attachment to their source and enjoy widespread popular use. We all utter Shakespearian or Biblical phrases all the time, but we don't associate "fight fire with fire" with King John or "nothing new under the sun" with Ecclesiastes. But when someone is the Wicked Witch of Something — there's still a kernel of Oz there. Now click your heels three times and go back to whatever you were doing.