“The Italian Renaissance author and diplomat Baldassare Castiglione was an early champion of cool, or what he thought of as studied carelessness, calling it ‘sprezzatura’. And his Book of the Courtier (1528) delineates in exquisite detail how to ‘practise in all things a certain nonchalance which conceals all artistry and makes whatever one says or does seem uncontrived and effortless’. As Castiglione understood, we value cool because we assume that those who act effortlessly must have plenty of resources in reserve for when bigger challenges arise. They exhibit a superfluity of fitness. Creating this appearance of ease is so valuable, Castiglione thought, that one should devote considerable effort to making it happen.” source — Some relate sprezzatura to the japanese concept of shibui — deliberate Miles Davis ref