Don Boudreaux of Cafe Hayek discusses the unintended consequences of legislation. From the YouTube description:
Some government regulations that are made with good intentions still lead to bad results. The Endangered Species Act is a good example of such a law. In this video, economics professor Don Boudreaux examines the Endangered Species Act, and uses it to explain how policymakers' good intentions sometimes go awry. While the law intends to preserve threatened animals, it actually has the effect of giving landowners strong reasons to kill any endangered species they find on their property. This phenomenon is known as "shoot, shovel, and shut up." Boudreaux implores us not to judge a policy by its intentions, but by its results. We can't assume a policy will be good just because the intentions of the policymakers are good.