- Have you ever wondered why there is a light in your fridge but not in your freezer? Or why 24-hour shops bother having locks on their doors? Or why soft drink cans are cylindrical, but milk cartons are square? The answer is simple: economics. For years, economist Robert Frank has been encouraging his students to ask questions about the conundrums and strange occurrences they encounter in everyday life and to try to explain them using economics. Now he shares the most intriguing - and bizarre - questions and the economic principles that answer them to reveal why many of the most puzzling parts of everyday life actually make perfect (economic) sense.