Keep up the good fight, never give up. I used to throw cents on the train tracks a lot when I was a kid. Not many nickels though. Those went to buy my comic books.
Yep, it's a nickel. Or was one, before it got flattened. How'd you find that? It wouldn't have fit inside a roll of nickels, and would be strange to see in circulation.
Only reason to do it is because you enjoy the opportunity to learn more about coins and have a little bug for finding something unusual. When those two facets of searching for errors fade, you tend to pay less attention to the coins passing through your hands. Collecting does not have to be about one aspect though so just enjoy what you enjoy and let your collecting evolve in the direction you find interesting in the moment.