Late on Christmas Day a young man named Joseph Yu left Bristol for London. He reached Oxford Street at 2am and stayed there for seven hours at what became the front of a queue several hundred people long for the winter sale at the Selfridges Gucci concession.

When the doors opened Mr Yu ran to the concession's male accessories subdivision in pursuit of a “manbag” normally priced at £600 but knocked down and down again by the credit crunch, retailer anxiety and the bag's failure to appeal to anyone else. He got what he wanted.

He did not need it. The carrier bag it came in would have served just as well for transporting manbag-sized items. But he should not be mocked. Nor should he - necessarily - be labelled a victim of the bargain hunter neurosis, which one self-styled money pathologist says involves anxieties “that may relate directly to maladaptive, self-defeating, irrational behaviour”.

No one claims that bargain hunting is rational. Reason does not come close to explaining why tens of thousands flooded on to the John Lewis website on Christmas Eve and into the country's shopping centres yesterday morning to buy things they had managed quite well without until that moment.

Bargain hunting is bonkers, deeply human and a social good. Every bargain bagged is a win for the hunter; a psychological lift no matter what the discount. It is cash for the retailer who would otherwise have faced a total loss, and safe passage to a caring home for one more consumer durable that would otherwise have gone straight to landfill. It is a win-win-win situation for desperate times, priced (in Mr Yu's case) at just £300.