charting question, page-7

I strongly believe that the sooner people learn to apply commercial reasoning to their finances the better.

I'm sure most people you know, who have contemplated a substantial investment, like buying a house or a business, will pound the streets, do reasearch, do due diligence, look at the books, ask questions, make sure there is no freeway planned behind their back fence etc.

Why abandon this commercial approach, when you buy a share of a listed company ?