Way back in the late 1970s, in my high school chemistry class we watched a film. It was trying to explain diffusion. There was a big fish tank filled with a bunch of gold and black fish. They were separated by a screen. When the screen was removed, the fish swam around until the colors were all mixed. The teacher remarked "There goes the neighborhood". I don't remember anyone laughing.
I had never heard that remark before. Imagine if a teacher said that today?
I heard that remark a few times later in life. When it was said, nobody was laughing.