Interest rate cuts have an effect in stimulating an economy by directly or indirectly making someone, somewhere, spend more than they otherwise would. That extra spending increases demand and ensures that we all carry on with work to do, without us having to slash our prices or our wrists.

Black Friday is not another bad hair day in Wall Street. It's the term used by American retailers to describe the day after the Thanksgiving Holiday, seen as the semi-official start of Christmas shopping season.

Even though disciplined sleeping habits and the adrenalin of live radio ensures that we are very awake while on duty, there is evidence of a phenomenon called circadian desynchronosis which causes one's brain to function slowly at those times of day when it thinks it should be asleep, regardless how wide awake the body is.

Once we are fed, heated, housed and healthy, our extra consumption inevitably has an element of luxury about it. And once luxury enters the scene, the practicalities are in trouble, as women who wear expensive stiletto heels can testify.

It is no wonder that bank capital is regulated. When borrowing and lending is profitable, it is tempting for banks to scale up their operations and to borrow and lend too much in relation to their capital, in effect reducing the effectiveness of the potential capital cushion.

We Brits print banknotes out in Debden in Essex, and have contracted it out to the private sector. Here in the U.S. it is a government operation right in the heart of Washington next door to the Holocaust Museum.

Interestingly, human irrationality is a hot topic in economics at the moment. Behavioural economics it's called, on the cusp of economics and psychology.