The reason advertising is governed by fear, after all, is that most agencies rely on just a few clients to bring in the lion's share of their revenues.

Political risk is hard to manage because so much comes down to the personal choices of policymakers, whether prime ministers or heads of central banks.

Publishers, naturally, loathe used books and have developed strategies to depress the secondhand market. They bring out new, even more expensive editions of popular textbooks every three to four years, in a classic cycle of planned obsolescence.

In conditions of uncertainty, humans, like other animals, herd together for protection.

Breaking tasks down into smaller sub-tasks can be very useful.

Technological innovation has dramatically lowered the cost of computing, making it possible for large numbers of consumers to own powerful new technologies at reasonably low prices.

When Americans are asked to rank professions in terms of honesty and ethics, insurance agents routinely end up near the bottom of the list - somewhere between politicians and car salesmen. Generally, insurers are seen as clever hucksters who prey on insecurity and ignorance to sell people what they don't need at prices they shouldn't have to pay.