Seconds, hours, and weeks are all human inventions. Only by marking them off, wrote historian Daniel Boorstin, “would mankind be liberated from the cyclical monotony of nature.” — *location: 168* ^ref-55801 --- Positive affect—language revealing that tweeters felt active, engaged, and hopeful—generally rose in the morning, plummeted in the afternoon, and climbed back up again in the early evening. — *location: 191* ^ref-9285 --- For analytic problems, lack of inhibitory control is a bug. For insight problems, it’s a feature. Some have called this phenomenon the “inspiration paradox”—the idea that “innovation and creativity are greatest when we are not at our best, at least with respect to our circadian rhythms.” — *location: 395* ^ref-31927 --- What ultimately matters, then, is that type, task, and time align—what social scientists call “the synchrony effect.” — *location: 492* ^ref-62900 ---