A column in the New York Times has the headline, "Should We Tax People for Being Annoying?"
a. Do annoying people cause a negative externality? Should they be taxed? Do crying babies on a bus or plane cause a negative externality? Should the babies (or their parents) be taxed?
b. Do people who plant flowers and otherwise have beautiful gardens visible from the street cause a positive externality? Should these people receive a government subsidy?
c. Should every negative externality be taxed? Should every positive externality be subsidized? How might the government decide whether using Pigovian taxes and subsidies is appropriate?