Netflix’s adaptation of 13 Reasons Why has finally arrived online, much to the delight of its target teenage audience – but the adaptation of Jay Asher’s 2007 novel isn’t just for young adults.

In fact, it presents a powerful message that viewers of all ages need to heed.

It’s oddly apt that the series arrived on the UK’s National Kindness Day, because Hannah Baker’s tale serves as a chilling reminder of what can happen when we’re cruel – and just how much those nasty “little things” we do and say really matter. 

In episode three Hannah – who has taken her own life and is revealing the 13 reasons why from beyond the grave via a series of cassette tapes – delivers what is essentially a 60-minute monologue about just one of the “little things” that pushed her down a dark path. Be warned, the show eventually follows her - that's why it's rated 18+.

“Chaos theory isn’t exactly about chaos,” she warns. “It’s about how a tiny change in a big system can affect everything."

“Maybe you think I’m silly, I’m some stupid girl who gets worked up over a little thing. But little things matter,” Hannah tells her former friend Alex, who put her name on a “stupid list” ranking the school’s best and worst looking girls. That list caused a rift between Hannah and her best friend Jessica, and made it “open season” on our poor narrator, who became a subject of ridicule among the boys and girls in school. 

“Maybe you say it’s nothing Alex, it’s just words,” Hannah continues – but they're never "just" words. “Slut” is a particular favourite among her classmates’ arsenal, a four letter term that starts the ball rolling toward the point of no return.

13 Reasons Why recaps

Episode 1: Why did Hannah Baker take her own life?

Episode 2: "Complicated" friendships have fatal consequences"

Episode 3: Now we know how much the "little things" matter

But don’t just take it from Hannah Baker, the fictional teenager whose life and death tale has been a source of comfort for millions of young adults who say Jay Asher’s novel saved their lives. Take it from the adult who sat close to tears for 60 minutes, watching an all-too familiar sequence of events.

I was just fifteen years old when a few false words blew my whole world apart. At the time, I too felt like a “stupid girl” who was getting “worked up” over something small. But when – like Hannah – I walked down a hallway with all eyes on me and heard the whispers of my classmates, I realised little words had the power to unleash chaos.

That chaos ultimately became so unbearable that, after coming close to the edge myself, I packed my bags and left school. 

My own story is nothing special. In fact, it’s depressingly common. Every day in homes, schools and workplaces, people just like you and I push men, women and children to the edge.

Some, like me, resurface. Others, like Hannah Baker, don't.

Just two weeks ago ITV’s This Morning launched a Be Kind campaign inspired by the fact that they'd heard too many tales of young lives lost as a result of bullying. It's since been backed by the Secretary of State for Education, Justine Greening, and supported by almost 200,000 families and youth organisations throughout the UK, who have taken a pledge to teach their children about how harmful bullying can be.

It doesn’t just take a concentrated online bullying campaign or a brutal beating to break someone. Something as small as an unkind word can prove fatal if it lands in the right place at the right time. And it often comes as part of a continous psychological campaign, endlessly sustained by a long line of unwitting participants. 

“You never know what’s going to hit how,” says Tony, the custodian of Hannah’s cassette tape confessions. “You really don’t know what’s going on in someone else’s life.”

Even Hannah acknowledges that most of the people who hurt her probably had no idea that what they were doing. 

About a decade after my own experience, I wrote a piece about the bullying I'd endured - without naming names - and was contacted by the very person who’d told the lie that turned my world upside down. She was furious to hear that anyone could have done something so cruel to me, and offered her full support. 

While my world had ended, her life had carried on undisturbed, and she’d totally forgotten the whole thing ever happened. She was completely convinced - much like Hannah's fictional friends - that she'd never have the capacity to cause harm to anyone.

Just like Alex putting Hannah's name on that fateful list, telling a horrid lie about a school friend didn't sound like something she would do. But it was.

We ALL have the capacity to be that theoretical butterfly that flaps its wings in just the right time and just the right place, and causes a hurricane thousands of miles away. We'd be foolish to think otherwise.

“Why don’t they put up a poster that says try not being a dick to people?” a guilt-ridden Alex screams as he tears down the 'Suicide is not an option' and 'Please talk' support posters littering Liberty High’s halls after Hannah’s death. 

It's a message he wishes he'd heeded before scribbling on that piece of paper, and one we could all do with remembering when we're tempted to say or do “little things” ourselves.

13 Reasons Why is available on Netflix now