Reassurance can actually exacerbate anxiety: when you reassure your friend that the worst-case scenario he fears probably won't occur, you inadvertently reinforce his belief that it would be catastrophic if it did. You are tightening the coil of his anxiety, not loosening it. All to often, the Stoics point out, things will not turn out for the best.

True security lies in the unrestrained embrace of insecurity - in the recognition that we never really stand on solid ground, and never can.

...It's more important than ever that we find new ways to cultivate curiosity - because our careers, our happiness, and our children's flourishing all depend upon it.

Confronting the worst-case scenario saps it of much of its anxiety-inducing power. Happiness reached via positive thinking can be fleeting and brittle, negative visualization generates a vastly more dependable calm.

Ask yourself whether you are happy', observed the philosopher John Stuart Mill, 'and you cease to be so.' At best, it would appear, happiness can only be glimpsed out of the corner of an eye, not stared at directly.

Who says you need to wait until you 'feel like' doing something in order to start doing it? The problem, from this perspective, isn't that you don't feel motivated; it's that you imagine you need to feel motivated. If you can regard your thoughts and emotions about whatever you're procrastinating on as passing weather, you'll realise that your reluctance about working isn't something that needs to be eradicated or transformed into positivity. You can coexist with it. You can note the procrastinatory feelings and act anyway.

The routines of almost all famous writers, from Charles Darwin to John Grisham, similarly emphasise specific starting times, or number of hours worked, or words written. Such rituals provide a structure to work in, whether or not the feeling of motivation or inspiration happens to be present. They let people work alongside negative or positive emotions, instead of getting distracted by the effort of cultivating only positive ones. ‘Inspiration is for amateurs,’ the artist Chuck Close once memorably observed. ‘The rest of us just show up and get to work.