Pareto's principle

And since I cited Sturgeon in the previous post, let me cite italian economist Pareto in this one (rip/mix/burn from Wikipedia):

He made several important contributions especially in the study of income distribution and in the analysis of individuals' choices. He introduced the concept of Pareto efficiency and helped develop the field of microeconomics.

Oh, why should I copysomeone else's words? Ok I don't have time just go there and have a look at it. You will not regret it - economist are actually fine people - and I am pretty sure Pareto would have enjoyed a conversation with Steven D. "Freakonomics" Levitt ;-)