It's what pretty much all coins look like that have been used for 75 years, pockets, hands, cars, vending machines, maybe spent a year in a parking lot, a woman's purse, maybe a man's purse..
Maybe some kid used it in 1962 to buy 2 issues of amazing fantasy issue 15 with the introduction of spiderman and a piece of penny candy. Maybe it was a GI's lucky pocket coin at the end of WWII and that was just it's beginning.
Who know's what stories that quarter could tell, but it's seen a lot of action.
I don't see an error on it, but I see a quarter with a heck of a lot of history and wear from where it's been.