Futurists always measure their batting average by counting how many things they have predicted that have come true. They never count how many important things come true that they did not predict. Everything a forecaster predicts may come to pass. Yet, he may not have seen the most meaningful of the emergent realities or, worse still, may not have paid attention to them. There is no way to avoid this irrelevancy in forecasting, for the important and distinctive are always the results of changes in values, perception, and goals, that is, in things that one can divine but not forecast. (Peter Drucker)

[h/t to Jess]