“The only way to prepare for the unexpected is to build into all of your plans a contingency clause that suggests what you would do if the unexpected happened. In that way you will have alternative routes ready to take in case the main route is closed unexpectedly, as well as established procedures for changing your plans with a minimum of chaos if they are undermined by unforeseen events. There is a further advantage to worst-case scenarios: if everyone else, as the Macrae quotation suggests, is going the way you were planning to, the worst-case scenario becomes a forecast that may be accurate simply because it is based on something other than commonly accepted assumptions. “Contrarian” investment strategies are based on precisely this approach.”