"Reliance on models based on incorrect axioms has clear and large effects. The Black?Scholes model[8], for example, which was invented in 1973 to price options, is still used extensively. But it assumes that the probability of extreme price changes is negligible, when in reality, stock prices are much jerkier than this. Twenty years ago, unwarranted use of the model spiralled into the worldwide October 1987 crash; the Dow Jones index dropped 23% in a single day, dwarfing recent market hiccups."
Sort of like the "100% gain on property every ten years, so lets load up on deb"t formula.