It would be lovely to think I had become a genius," he smiles, "but the fact is that I've forgotten most of it. Occasionally I can be watching Univer… - Bill Bryson

On Fifth Avenue I went into the Trump Tower, a new skyscraper. A guy named Donald Trump, a developer, is slowly taking over New York, building skyscrapers all over town with his name on them, so I went in and had a look around. The building had the most tasteless lobby I had ever seen — - all brass and chrome and blotchy red and white marble that looked like the sort of thing that if you saw it on the sidewalk you would walk around it. Here it was everywhere — - on the floors, up the walls , on the ceiling. It was like being inside somebody's stomach after he'd eaten pizza.

Your brain is marvellously efficient. It requires only about 400 calories of energy a day — about the same as you get in a blueberry muffin. Try running your laptop for 24 hours on a muffin and see how far you get.

What this means in practice is that if you are not a born worrier you have nothing to worry about (though of course you wouldn't be worrying anyway), whereas if you are a worrier by nature there is absolutely nothing you can do about it, so you may as well stop worrying, except of course you can't.