The perimeter of the board for the game Ticket to Ride has numbered spaces for score keeping. When a player earns points, they advance their token along the perimeter. Say I was on space 30 and scored 5 points. I would move my token "1, 2, 3, 4, 5" to space 35.
One day, I realized that since these spaces were numbered, unlike other board games, I could add instead of having to count the offset. And that, dear reader, is indexing. I don't have to inspect each space in my offset, I can advance directly to the final position.