It started out as a casual, innocent Sunday morning.
The sun was up. People were out and about. I was seated alone at a busy cafe, phone in hand, and had just placed an order for a much-needed Big Breakfast - also known as the world's finest hangover cure.
There was nothing at all to suggest an unimaginable bout of trauma was about to strike hard and ruin this fine day without warning.
And then my phone died.
Despite a reassuring-enough 36 per cent battery charge, the damn thing just shut off, stubbornly refusing resuscitation. Bloody iPhones.
As the weight of this deep-seated tragedy dawned on me, I looked up, stared around in horror at all of the chattering groups of people oblivious to my dire first-world predicament, and helplessly looked back down at my blank device.
Nothing. Nothing but that hideous connect-me-to-a-USB-port sign, mocking me for all it was worth. Siri herself may have burst out just long enough to say something bitchy about my lack of friends in that unnecessarily icy voice she reserves for Apple users.
Suddenly, I faced a frightening but interesting thought: what do I even do now? How can anyone just sit there - whether it's at a cafe, on a train or just at home - without some form of stimulation?
Ask yourself this: when was the last time you actually sat down - with absolutely no distractions - for an extended period of time? As in: no smartphone, no people to speak to, no newspaper to read and no music to listen to.
Sitting there with nothing to do but wait for my overpriced breakfast to arrive was the first time I properly realised I never allow myself to be alone with my own thoughts.
In an era where our smartphones are an extension of our arms and we're connected to the internet 24/7, is there anybody who can actually say they've genuinely honed the skill of being comfortable inside their own head? That can enjoy extended time off work without craving the buzz of the office, or needing to be out with friends constantly?
Introverts - people who prefer to relax and recharge by being alone - are sometimes derided in the public sphere. They're miscast as shy, antisocial, or too weird to have social plans. But I can't think of a more liberating skill than being able to enjoy your own company.
The struggle to do so is more common than you might think. Dr Samantha Boardman, a clinical instructor in psychiatry, wrote a great article in the Wall Street Journal last week called Why Doing Nothing Is So Scary - And So Important, where she detailed just how challenging downtime is for many of her patients.
She said we're now part of an era where everybody from high-powered executives to children struggle with filling free time. Whether we're listening to music while exercising or watching TV before bed, every moment is filled. From the moment we wake up to the moment our head hits the pillow, we never stop. And that right there is the beginning of a burn-out.
In 2014, a series of studies were conducted in which researchers put subjects in a windowless room with no distractions. The task? To simply just sit there, in that empty room, and do nothing but think.
The researchers were shocked to find a lot of the subjects voluntarily gave themselves painful electric shocks to break their boredom. Two-thirds of men, and a quarter of women, pressed a button to deliver a number of painful jolts during their 15 minutes of solitude. One man even shocked himself 190 times.
Imagine that. His need for stimulation was so strong that he opted to deliberately, repeatedly hurt himself over feeling nothing at all.
Countless studies have been conducted into how solitary confinement is the worst kind of psychological torture. It's been reported that being confined to a Solitary Housing Unit - in which a person is held in isolation for at least 22 hours a day - can cause irreversible psychological damage in just two weeks. For some, it can manifest in less time. The intentional deprivation of stimulation is sometimes described as a torture method, with a United Nations report from 2011 condemning it as such.
OK, obviously we can't equate indefinite solitary confinement in prison to sitting alone for 15 minutes, but the point is it has been proven that humans - by nature - inherently struggle to cope with isolation. And now that we're more frequently connected to and invested in the wider world than ever before, that struggle is only greater.
So what's the solution? Dr Boardman said the one thing she prescribes her patients to do is to spend at least 15 minutes every single day of doing absolutely nothing. The whole point, she said, is to shift the way we think about free time - instead of seeing it as a source of anxiety, it becomes a privilege, and that shift in mindset is the foundation for being able to enjoy vacations and time off without craving constant stimulation.
Give it a try. And if you ever manage to master the art of spending time alone, please share your wisdom with me.