Just think about the choices we make every day, whether it is the food we buy from supermarkets, with their 300,000-plus lines; the schools we choose to send our kids to; the cars we select to drive; the phone service we opt for; the healthcare plans; the pension options; where to take a holiday - the multiplicity of choices means that we have to research, consider and decide what we want. Choice has become an all-consuming task, but it doesn't necessarily improve the service or the product. Take telephone directory enquiries, for example. It used to be so simple - one number, one service. And it worked. Now we have a number of services, none of which seem capable of finding the number you need.

"I've attempted to explain why and when an excess of choice becomes a problem," Schwartz says. "When you have all these choices, you have an enormous problem gathering all the information to decide which is the right one. You start looking over your shoulder, thinking that if you'd made a different choice, you'd have done better. So there's regret, which makes you less satisfied with what you have chosen, whether or not there's good reason to have regrets. It's easy to imagine there was a better option, even if there wasn't really, because you can't possibly examine all of them."