 And now, great moments and unintended consequences. Part one, siege sales. The year, 1585. The problem, the Spanish army is besieging Antwerp, shelling approaching merchant ships and causing food prices inside the city to rise. The solution, enact strict price controls on food. Sounds like a great idea, with the best of intentions. What could possibly go wrong? It turns out merchants don't like risking their live ships in Congo, especially when their goods fetch the same prices at ports without incoming cannon fire. Artificially low prices also fuel demand, causing food supplies inside the city to plummet. It wasn't long before Antwerp surrendered, given the city government blockaded itself far better than any army ever could. Part two, chimney cheapskates. The year, 1662. The problem, Charles II needs more money. The solution, a hearth tax. Since the number of fireplaces in a building is considered a proxy for wealth, this progressive property tax scheme was sure to be a hit. Sounds like a great idea, with the best of intentions. What could possibly go wrong? It turns out people don't like paying taxes. They also don't like petty constables and subcontractors entering their homes to count stoves. Many stopped up their chimneys to avoid the taxes. One intrepid baker even knocked through the wall from her oven to access her neighbor's chimney, causing a fire that destroyed 20 homes and killed four people. And since the revenue generated was less than expected, it wasn't long before the hearth tax also went up in smoke. Part three, cash for clunkers. The year, 2009. The problem, a recession. And we need to save the environment and domestic manufacturing, plus something about economic inequality. And, you know, maybe juice the reelection campaign, all that, all that was the problem. The solution, give away $1 billion in incentives to U.S. residents who destroy their old vehicles for more fuel-efficient new ones. Sounds like a great idea, with the best of intentions. What could possibly go wrong? It turns out people like free money. The program blew through the original allocation in less than a month. So Congress approved an additional $2 billion, which was gone a month later. Another thing people like, driving their new cars. While the program did increase average fuel economy in the United States by 0.65 miles per gallon, total fuel consumption actually rose more than 800 million gallons in 2010. As for the economy, the boost in vehicle sales was fully offset by a fall-off once the program ended. In fact, for every job created, the government spent $1.4 million on the program. But did it help U.S. car manufacturers? Not really. Only two of the top 10 models sold as part of the program were domestic brands. And apparently, destroying an entire generation of used cars causes remaining used car prices to rise. But hey, those are just the kinds of vehicles less affluent people buy. The kind donated to charities or sold to poor countries where they replace even older, less fuel-efficient vehicles. And about that reelection campaign? Well, I think it's important that we consider great moments in unintended consequences, good intentions, bad results. Do you have an idea for a future episode? Put it in the comments below. We might use them or not. Who knows?