The Greatest Mistake Jared Diamond, author of Guns Germs & Steel debunks the widely held notion that the shift from hunter-gatherer to farming societies improved the life of human beings 10,000 years go. However, I'm not quite sure if this is The Worst Mistake in the History of the Human Race (that remains the election of certain modern-day Bushmen) :

To science we owe dramatic changes in our smug self-image. Astronomy taught us that our earth isn’t the center of the universe but merely one of billions of heavenly bodies. From biology we learned that we weren’t specially created by God but evolved along with millions of other species. Now archaeology is demolishing another sacred belief: that human history over the past million years has been a long tale of progress. In particular, recent discoveries suggest that the adoption of agriculture, supposedly our most decisive step toward a better life, was in many ways a catastrophe from which we have never recovered. With agriculture came the gross social and sexual inequality, the disease and despotism, that curse our existence.

At first, the evidence against this revisionist interpretation will strike twentieth century Americans as irrefutable. We’re better off in almost every respect than people of the Middle Ages, who in turn had it easier than cavemen, who in turn were better off than apes. Just count our advantages. We enjoy the most abundant and varied foods, the best tools and material goods, some of the longest and healthiest lives, in history. Most of us are safe from starvation and predators. We get our energy from oil and machines, not from our sweat. What neo-Luddite among us would trade his life for that of a medieval peasant, a caveman, or an ape?  ¶ 5:57:00 AM