The pieces that stuck: "As human beings, in other words, we can only handle so much information at once. Once we pass a certain boundary, we become overwhelmed. What I'm describing here is an intellectual capacity — our ability to process raw information. But if you think about it, we clearly have a channel capacity for feeling as well. ¶ ...To be someone's best friend requires a minimum investment of time. More than that, though, it takes emotional energy. Caring about someone deeply is exhausting. At a certain point, at somewhere between 10 and 15 people, we begin to overload, just as we begin to overload when we have to distinguish between too many tones. It's a function of the way humans are constructed."
"We have trouble estimating dramatic, exponential change. We cannot conceive that a piece of paper folded over 50 times could reach the sun. These are abrupt limits to the number of cognitive categories we can make and the number of people we can truly love and the number of acquaintances we can truly know. We throw up our hands at a problem phrased in an abstract way, but have no difficultly at all solving the same problem rephrased as a social dilemma. All of these things are expressions of the peculiarities of the human mind and heart, a refutation of the notion that the way we function and communicate and process information is straightforward and transparent. It is not. It is messy and opaque."
— Malcolm Gladwell, The Tipping Point: How Little Things Can Make a Big Difference