No skill is more valuable and harder to come by than the ability to critically think through problems that you haven’t encountered before. Good thinking makes the future easier, while poor thinking makes it harder. Good thinking means better decisions. Better decisions allow for more free time, less stress, and more opportunity. Poor thinking, on the other hand, leads to decisions that consume time, reduce options, and increase our stress.

High multitasking can be called "mental filing". Multitasking, in short, is not only not thinking, it impairs your ability to think. Thinking means concentrating on one thing long enough to develop an idea about it. Not learning other people’s ideas, or memorizing a body of information, however much those may sometimes be useful. Developing your own ideas. In short, thinking for yourself. You simply cannot do that in bursts of 20 seconds at a time, constantly interrupted by Facebook messages or Twitter tweets, or fiddling with your iPod, or watching something on YouTube.