Here are seven great things I read this week. 

Strategy

Shane Parrish shares a great Buffett story:

"He gave us a quiz," Buffett said, "A true-false quiz. And there were all these guys who were very smart. He told us ahead of time that half were true and half were false. There were 20 questions. Most of us got less than 10 right. If we'd marked every one true or every one false, we would have gotten 10 right."

Graham made up the deceptively simple historical puzzler himself, Buffett explained. "It was to illustrate a point, that the smart fellow kind of rigs the game. It was 1968, when all this phony accounting was going on. You'd think you could profit from it by riding along on the coattails, but (the quiz) was to illustrate that if you tried to play the other guy's game, it was not easy to do.

Cool head

This is a fascinating look at people who can keep their cool:

All bomb-disposal operatives are good. Otherwise they'd be dead. But what did the stars have that the lesser luminaries didn't? ...Whereas the heart rates of all the operatives remained stable, something quite incredible happened with the ones who'd been decorated. Their heart rates actually went down. As soon as they entered the danger zone (or the "launch pad," as one guy I spoke with put it), they assumed a state of cold, meditative focus: a mezzanine level of consciousness in which they became one with the device they were working on.

Crash

Josh Brown shows the number of market crashes and pullbacks that didn't occur during recessions:

Pick sides

The economy has been shocked by government shutdowns and debt-ceiling debates for the last four years. This Pew study shows why: Americans are as polarized as ever:

Retention 

Starbucks (SBUX -0.35%) found a smart way to keep people in its coffee shops:

American coffee giant Starbucks is giving its customers another way to power up their devices in-store, besides those outlets everyone fights over. The new initiative involves a partnership with Duracell Powermat to provide wireless charging in Starbucks and Teavana locations across the U.S., starting in San Francisco and rolling out gradually from there. 

Tops

Michael Batnick explains why calling tops is so hard:

Bull market tops are more difficult to call than bear market bottoms because doubt is a far more resilient emotion than hope. The under- invested cling to doubt in bull markets but the fully invested quickly abandon hope in bear markets. This is why the average bull market lasts 45 months while the average bear market only lasts 10 months.

Conservative

Investors still love cash:

According to new research on investors in 16 countries by State Street's Center for Applied Research, retail investors globally were holding an average of 40 percent of their assets in cash, up from 31 percent two years ago. That's a compounded annual growth rate of a whopping 13 percent.

Enjoy your weekend.