The curse of untidiness;
The clutter industry feeds the addiction. Self-storage has been the fastest-growing part of America's commercial-property business in the past 30 years. There are now almost seven square feet of self-storage for every American. Paying more to store something than it is worth may seem doubly irrational. But it enables people to reconcile caveman clutter with modern minimalism, and allows companies to benefit from a huge business opportunity that includes inflatable salad bars, over-door baseball cap organisers and motion-activated paper-towel dispensers. Since the urge to accumulate stuff is limitless, so is the scope for selling people stuff to keep it in.
The endowment effect;
The endowment effect was controversial for years. The idea that a squishy, irrational bit of human behaviour could affect the cold, clean and rational world of markets was a challenge to neoclassical economists. Their assumption had always been that individuals act to maximise their welfare (the defining characteristic of economic man, or Homo economicus). The value someone puts on something should not, therefore, depend on whether he actually owns it. But the endowment effect has been seen in hundreds of experiments, the most famous of which found that students were surprisingly reluctant to trade a coffee mug they had been given for a bar of chocolate, even though they did not prefer coffee mugs to chocolate when given a straight choice between the two.