It is probably the first RPM that new collectors find. I know it was mine. I bought a bag of 1200 circulated wheat cents. I searched the bag and found a bunch of junk the first time. I didn't have anything interesting/worth collecting. My mentor suggested checking again. So I check all of them again and boom, there it was. I was so happy I found my first RPM. He suggested looking a third time and I found two more the next time around. My eye hadn't picked up what I was looking for the first time around, and started developing the second/third time around. All three were different RPMs. I've been hooked ever since.
The Kicker: When I found the first RPM, I asked about value and they told me $2.50. I was happy. But then they told me a BU example would be worth 10X that. So that was my last bag of circulated wheats. I moved to BU rolls after this happened. (That was back when you could get many rolls cheap.) Now I just check what I can find.