I believe that pennies are simply no longer useful as a means of exchange. As Greg Mankiqw states: “When people start leaving a monetary unit at the cash register for the next customer, the unit is too small to be useful.” We only keep these units of currency around for sentimental value. If we don't drop the penny then we will continue wasting resources and causing toxicity to both people and the environment through the creation of pennies. Tell me I'm wrong, I'll wait.