LEAVING high office “to spend more time with the family” has entered the catechism of political cliché. The sudden enthusiasm which the “disgraced-formers” and the “honoured-to-have-served” of every political stripe show for their domestic lives – once they’ve been invited or compelled to surrender their ministerial boxes and cars – can provoke easy cynicism.

But emotionally, this response makes a good deal of sense. All our lives, all our egos, are suspended midair by the ties to life which make us who we are. You know: all the things that make us feel purposeful and significant, meaningful and loved. Life will always hurdy-gurdy you about. The emotional webs holding you up will tense and stretch under the stresses and strains.

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But when one guy rope in your life frays and snaps, you’ve got to rest your weight on another line. Dumped by your man? Screw that. At least you’ve got a decent job. Get your jotters at work? You can console yourself with the love of a good woman. Dumped, sacked, shamed and evicted? Well its never too early to harden those mental associations between misery and alcohol. Bottom line? The whole world may think you are a crashing buffoon, a disaster, but chances are, your mammy still loves you.

Relative failure has always interested me more than success. More often than not, success is boring. Don’t believe me? Listen to just about any leading athlete being interviewed about the gold medal they’re clutching or the trophy they’re lifting. Struggles and setbacks, triumphs which dissolve into disasters and catastrophes which suddenly reverse themselves – that’s the stuff real drama is made of. Success is just the eye of the hurricane, where the air feels oddly dead and still.

Big political reshuffles have all this and more. Most of us have the benefit of being canned from work without a slavering phalanx of journalists poised to itemise the mediocrity or scandal which precipitated our departure. Tweeting as this week’s reshuffle unfolded, the former Scottish Government minister and political refugee Marco Biagi encouraged folk to “remember these are actual human beings … people with feelings and the rest of it”.

Shona Robison’s widely quoted letter to the First Minister gave vivid expression to Marco’s point. “As you know this last year has been particularly challenging for me personally, losing both of my parents, having a health scare of my own, and some big changes in my personal life,” Robison wrote. Public affairs is about public choices and public actions. You might sympathise with a politician’s sticky personal life, but their public activity must be fair game. But now and then, it is good to be reminded of the hidden hinterland our politicians work against.

Sometimes, you’re afforded little glimpses into these. For others, their struggles come as revelations. Theresa May’s acute social anxiety is one of the few features of this Prime Minister’s personality I have some sympathy with. Smiles freeze on her face. The PM has the physical ease of a broken umbrella. She delivers set-pieces to camera like a pupated moth, painfully discharging itself from its chrysalis. I like her better for her social unease, but by gum, it must make her life hard. Does that excuse her woeful administration? Not a bit of it. But you won’t understand the whole picture without it.

The psychology of political commentary tends to assume that politicians can be neatly divided into their public and private personas. Political biographies hold out the promise of revealing “the real Theresa May”, “the private Salmond” or “Tony Blair’s secret side” by inducing the subject’s friends and enemies to wipe away the political greasepaint to reveal their true appearance, lovely or unlovely.

But I’m not sure this binary psychological thinking is particularly illuminating. To be sure, many politicians – like all showmen – seem able to sustain remarkable Jekyll and Hyde personalities, turning only smiling faces towards the cameras, while behind the scenes it is Hyde, Hyde, Hyde. But the effect of being involved for any time in public life seems even stranger.

The standard story says that politicians develop strategies to present their most appealing face to the electorate. These masks are lovingly cultivated, responding to public perceptions, media training, and the unforgiving apparatus of modern public relations. The metaphor implies the face beneath the mask remains hidden but unaltered. Not so. Or at least, not so in my experience.

The ancient Greeks had it right. Character isn’t something static. Your character isn’t fashioned by nature, fixed and immutable. Your character is a habit. Your character is how you behave. If you get into the habit of being dishonest, in time, you will become a dishonest character. If you practise empathy, you’ll become an empathetic soul. The idea of the good person who constantly does bad things is the worst of self-deception.

As Kurt Vonnegut said, we become “what we pretend to be, so we must be careful about what we pretend to be”. Often as not, when you try to pull away the mask a politician has worn for years, the face comes off with it.

Interviewed this week by BBC Scotland’s Edie Stark, Kezia Dugdale reflected on her bumpy spell as leader of the Scottish Labour Party. Dugdale characterises herself as “very green-eared” wanting “everybody to like her, and think she’s doing a good job”. Taking over from Jim Murphy, she learned that “emotional armour” was a prerequisite for working at the highest level in Scottish politics, a “coping mechanism” to deflect the thunder of criticism she received from all sides. So much, so familiar. But here Dugdale gets more interesting. There were, she told Stark, psychic costs to the carapace she erected around herself. “You lose that ability to empathise and to understand and to use emotional language,” she said. “There’s undoubtedly occasions when I look back now and think ‘I didn’t particularly like myself that day’ – I didn’t like who I was or what I was becoming – and that was a small part of why I resigned at the end of the day.”

You may not have made much of Kezia Dugdale’s tenure as leader of her party. You may think she was miscast in the role, made bad calls and bad political arguments. But what she told Edie Stark is real wisdom. You become what you pretend to be. Be careful what you pretend to be. And if you find you can’t live like that? If you find politics is twisting you out of all recognition? Hit the road, Jack. For your own sake, for your family: run a mile.