The Pareto Principle; The 20/80 Rule

In my undergrad accounting classes (yes, once upon a time I considered being an accountant, but I digress), we discussed the 20/80 Rule as it applied to accounting and business organizations: that is, that 20% of a firm's receivables would come from 80% of its clients; 20% of its payables would go to 80% of its vendors, etc. This "rule" was derived from, and the "principle" named after, the work of the early twentieth-century Italian economist Wilfredo Pareto, who discovered that 20% of Italy's people owned 80% of Italy's accumulated wealth. It is also important to note that this rule only applies in systems comprised of independent variables (e.g., people).

I have found that the 20/80 Rule applies to many situations in life -- not only the aforementioned, but also (a) I spend 80% of my time dealing with 20% of my friends and acquaintances; (b) I spend 80% listening to 20% of my CDs in a given time period; (c) 20% of a given population will cause 80% of its problems, or contribute 80% of its innovations. Then there's Tadeusz's spin on the 20/80 rule -- 10% of a given population will be saints (Mother Teresa, Saint Francis, Buddha, Jesus, etc.) and 10% will be irredeemable, destructive and complete assholes (e.g., Hitler, Stalin, Timothy McVeigh, G.W. Bush, etc.), while the remainder falls in between those two poles -- as well as W.E.B. DuBois's "Talented Tenth" variation thereof.

Thoughts? Discuss!