The bodyguard, Dan Clark, didn’t mean for it to hurt, he was just demonstrating a fighting move called the brachial stun. That’s a strike to the side of the neck using a chopping motion with the hands — but when Clark hit me with it in a slow speed demonstration, the sudden burst of force whipped my whole head to the right, crashing my teeth together so hard that I thought I would lose a filling. That’s what Dan Clark is like — even his demonstrations are intense. He’s the kind of guy who throws around phrases like the “muay Thai clench with a double knee strike,” and who, when he emails you to invite you to his training session, reminds you politely to bring a cup. All of it — the gym, the training, and especially the punch — combine to send a clear message: Don’t mess with Buffett, or any of Clark’s other clients. And that’s kind of the point.