The Difference Between 0 And Null

Finally, a visual representation that my brain can process! Zero is an empty toilet paper roll that still exists and serves as a placeholder. Meanwhile, NULL is when the entire roll is missing—it's not just empty, it's gone, non-existent, undefined. The cardboard tube has left the building.

This is exactly what keeps junior devs up at night. Zero is a legitimate value saying "there's nothing here, but I'm counting it." NULL screams "I refuse to acknowledge this variable's existence." And both will break your code in spectacularly different ways when you least expect it.