The organization started charging only because the U.S. Secretary of War asked it to. British soldiers had to pay for their snacks, and the free doughnuts for Americans were causing tensions. So the Red Cross complied, after protesting to no avail. It didn't last long — for most of the last 70 years, Red Cross doughnuts have remained free — but veterans haven't forgotten.

Chalk it up to something called categorical change, says Uri Simonsohn, a University of Pennsylvania business professor.