Economics is Easy, Applying it is Hard

Russell Roberts up at Cafe Hayek has a very good post on the topic of whether economics is easy or not, read on. What I find more interesting though is his quote from Milton Friedman:

"Economics is easy. All you have to remember is that people act in their own self-interest and demand slopes downward. It's applying these insights that's hard."

Steven N.S. Cheung has almost said the same thing using the same language, albeit in Chinese in his three volume works entitled "Economic Explanations".

Another thing I notice is that it seems no longer common for economists to use the term Price Theory, instead they call it Microeconomics...as if there is no difference between the two.