Sheer devilment, you test the water, see if anyone is daft enough to pay the price before dropping it. Slightly off topic but l have a friend who is an artist, when he does an exhibition he needs to sell his paintings for between £90 -£120 to make a living. However for devilment he always prices one of them for £750, more often than not that one sells first as people think it must be better than the others.