Likely a few dollars means nothing to you so the act of pointing the nearly lost dollars is a similar small task (not withstanding the possibility the act could have a profound effect on the recipient depending on their situation).

When I was younger and we were struggling hard, we found a wallet in a store loaded with green bills. That money would have had immediate, real, positive impact for us, like gas money and food that we did not have. We turned in the wallet and did not bother counting the bills. The cashier might have pocketed the money, who knows. But hopefully the owner of the wallet got their stuff back. I think that act does cast a barometer on my and my wife's character. We did what was "right" -- the property was not ours and not ours to take. Did we feel good about it? Nope! It was just doing the right thing even though there was a touch of pain to it.