If there is a thirteenth floor in a building, it's probably missing its 11th and 12th floor.

Edit/Update: I've been viral for around 12 hours now. From the few comments I saw, most of them were like: "No, it means the 13th floor is the 11th floor because they skipped the 13th"<br><br>Well, this joke literally only works if they're gone. How can it be the 11th floor, yet be on the 13th floor. What's the point of even having a number on the button if it isn't the actual floor number? I think most people just didn't get the joke, which is fine, I've failed at giving a joke.