I have a running joke with my brother-in-law. Every time we say hello or goodbye, one of us tries to get the upper hand on the other with ‘the JFK handshake’. If you’re unfamiliar with the manoeuvre, it involves taking a normal handshake, cupping it with your left hand, looking your opponent in the eye and saying, “It’s warm, but not dominating” before they realise what you’re up to (JFK usually left the spoken part implied).

Handshakes seem to take up an inordinate amount of attention when people are making their way up the corporate ladder. According to the baseless advice spilled out across the internet, you can tell a lot about a person from the way they grab your hand when introduced — a modern-day reverse palm reading. A strong grasp and eye contact indicates confidence. A dead-fish slipperiness shows fatal weakness. A crushing grip means they’re trying too hard to look tough. And if they close in too early and end up shaking your fingers instead of your palm, they’re totally an Aries who overthinks handshakes and mildly panicked because they were trying to memorise your name, look comfortable in a suit and pretend they know what they’re doing at this prestigious event all at the same time. (Go easy on me him.)

This strange-when-you-think-about-it practice has been thrust back into the cultural consciousness recently, because of the man who’s been dominating most of the world’s headlines. Donald Trump is in many ways a walking corporate cliché, a man animated by the unquiet spirit of a highlighted how-to guide on being a savvy businessman. Someone obviously once told him that power is established in that first contact, and he’s taken the advice to an unsettling place. Not content with the simple my-hand’s-on-top-and-that’s-a-metaphor-for-our-relationship-now manoeuvre, he flails his limb like an arm-wrestling cheat trying to put his opponent off balance. I can’t imagine it actually does anything for the power dynamic he’s trying to establish. It certainly doesn’t inspire confidence that he has good judgment.

The main trouble with handshakes is that they’re not only seen to be revealing, they’re also instinctual. A friend of mine once announced he wasn’t shaking hands with people anymore, because it was an archaic, stupid ritual that didn’t even prove he wasn’t secretly carrying a dagger. Five minutes later I put my hand out to say goodbye and he grabbed it without thinking. He was furious with himself, but also reassured by my warm, not-dominating touch.