This week, I was involved in a real-life example of this confusion.
While getting ready to retire for the evening, I empty my pockets on my dresser and look to see if there is anything interesting. Since my only trip of the day was a local grocery store, I did not expect anything. As I looked at what I thought was 78-cents something did not look right. As it turned out, one of the quarters was not a quarter.
Mixed in with the change from my single transaction of the day was a 1979-D Susan B. Anthony dollar coin. Not only did the cashier make the mistake, but when I accepted the change I did not catch the difference.
A real-life example as to the reason why the Susie B. was not a successful coin!