It's a popular fact that 90 percent of the brain is not used and, like most popular facts, it is wrong. . . . It is used. One of its functions is to make the miraculous seem ordinary, to turn the unusual into the usual. Otherwise, human beings, faced with the daily wondrousness of everything, would go around wearing a stupid grin, saying, "Wow," a lot. Part of the brain exists to stop this from happening. It is very efficient, and can make people experience boredom in the middle of marvels.

—Terry Pratchett

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