Several days after I arrived in Havana I asked my host why all the toilet seats were missing. “We don’t use them here,” he replied, as if it were an ancient custom. I didn’t come across any toilet seats until several weeks later, when I visited the Swiss officials at the former U.S. Embassy while arranging my return to the United States. The toilet seats were my first encounter with Cuba’s shortage of consumer goods. Luxury items are rarely available and food is strictly rationed, except for such things as fish, beer, and soft drinks. Even sugar, Cuba’s principal…