It is amazing how much both happiness and efficiency can be increased by the cultivation of an orderly mind, which thinks about a matter adequately at the right time rather than inadequately at all times. When a difficult or worrying decision has to be reached, as soon as all the data are available, give the matter your best thought and make your decision; having made the decision, do not revise it unless some new fact comes to your knowledge. Nothing is so exhausting as indecision, and nothing is so futile.
Source: The Conquest of Happiness, 1930, chap.5: Fatigue<
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