It is clear now that Boris Johnson has a straightforward and easily understood plan to solve the hitherto intractable problem of Brexit. In fact he has the same solution for most if not all of the problems that assail this country. The answer is optimism – or “optimism on steroids”, the medicine his colleague Jacob Rees-Mogg recently prescribed for his soon-to-be leader.

This is a peculiarly American solution to a very British problem, and raises yet another parallel between Johnson and his American partner in coiffure, rhetoric and political style, Donald Trump. Much has been written about the similarities between the two leaders – the trimming of reality to convenience, the highly malleable (indeed reversible) points of principle, the charisma and appeal to the mob. But somehow it is the repeated sanctifying of optimism I find most disturbing.

My main objection to optimism is that it is silly – at least as silly as pessimism, although obviously optimism has a better sales pitch. For it seems to imply that an attitude of mind can guarantee an outcome. There is a sense in which, I suppose, you could frame this as vaguely true. It is certainly true of pessimism, which will tend to ground any projects before they start (hence its bad reputation).

Optimism has an altogether more positive image. In the US the idea of positive thinking has been entrenched in its national psyche since its foundation. And certainly, if you don’t believe that by hard work, fortitude and willpower you can achieve your dreams, then you are unlikely to bother to work hard, be wilful or practise fortitude according to this thesis.

The trouble is that America, like Johnson and, you could argue, the world economic order, survives on myth – an approximation of reality that serves our emotional needs. Myths are powerful. Georges Sorel, the 19th-century French philosopher, wrote of the “mobilising myth”. He was particularly referring to the general strike within socialism, but also the way in which entire nations such as the US – as well as revolutionary Russia – could be founded. Mussolini, an admirer, took Sorel at his word. He said: “Men do not move mountains; it is only necessary to create the illusion that mountains move.” Social myths, wrote Sorel, are not descriptions of things, but “expressions of a determination to act”.

If you wanted to flatter Johnson, an activity he clearly welcomes, you could suggest that he is himself at the centre of ardently trying to build a social myth for Britain. One aspect of that myth is Brexit itself, the idea that we can be “free” and “independent”, and reclaim the swashbuckling glories of yesteryear. But it is the positive thinking aspect of the myth that seems to be at the forefront of Johnson’s “thought”, if one can elevate his jabberings to such a level of credence. Believe it and it will come true. You could call it the WYWUAS principle. When You Wish Upon A Star.

Optimism gets things done. It has energy. That is its perpetual triumph over pessimism. But unfortunately, like pessimism, it is skewed. It leads to the very unwelcome emotion that pessimism seeks to avoid by pre-empting it, assuming failure in the first place. This emotion is disappointment – attended by its ugly henchmen, bitterness and resentment.

One doesn’t have to look far to discover the seething ranks of the disappointed – all at one time fervent optimists. What happens to all that frustrated energy? It turns sour. This means that reality cannot be allowed to cast clouds on the glorious dawn, so saboteurs must be manufactured.

If optimism does not produce the desired results, then optimism itself has been sabotaged – not by the realists but by the pessimists, otherwise known as traitors, those with a negative outlook, those, for example, in the civil service, business, the BBC and all the main metropolitan centres who do not have the correct attitude to guarantee the final (impossible) outcome that Johnson and his cohorts desire, a cake-and-eat-it Brexit.

Johnson may well raise the spirits of a cohort of Tory supporters – and even the electorate at large, since he clearly has an attractive personality and a new beginning is always a moment of new hope, however fleeting. But when dreams go bad, watch out. Disappointment is not a neutral force – it is dark and it is potent.

Reality is always a mixture of compromise and the lesser of evils

Given all the disappointment that this country has already had to face over the past few years, whichever wing of the Brexit argument you happen to be on, an unwelcome tipping point may be reached, wherein yet another misplaced outbreak of buoyancy leads to still deeper resentment and anger and a lashing out at anyone to whom blame can be attached for the agonising sensation of lost hope.

Perhaps it is optimism itself that is to blame. Perhaps optimism is the villain, not the hero it is always hailed as. Perhaps if we could soberly reflect that all actions have unexpected consequences, all positive outcomes have negative outcomes riding in their slipstream and that reality is always a mixture of compromise and the lesser of evils, then we might find a way out of this mess.

However, Johnson and his merry band of Pollyannas are unlikely to embrace such a strategy. It resembles reality far too much – and that is something, the country seems to be saying, we have had enough of, thank you very much. Sooner or later, though, reality always turns round and bites you. And the wound bleeds much more, and much more painfully, for optimists than pessimists, which makes them not merely perpetually fatuous – but also dangerous.

• Tim Lott is a journalist and author