Sixty-year old anecdote time!
I was at Golden Gate Park with my grandmother, at some pavilion that had gendering machines. One of the machines would, upon receipt of a quarter, drop a slug of plastic into a heated mold, and blow it into a little plastic bear, then dispense it. I had only a nickel, which I dropped in the slot. The machine returned my nickel.
Just to see what would happen, I kept inserting the nickel. After five tries, it kept the nickel. But it didn’t make a toy for me.
For all of you non-Americans, a quarter is a twenty-five cent coin, and a nickel is a five-cent piece. Also, WHY AREN’T YOU AMERICAN???
ETA: it was probably closer to fifty-five years. I didn’t have my multiplication tables learned when I was four.