The sight of it makes every millennial's blood run cold. With its blank finality, lack of warmth, and overtones of passive aggression, there is no punctuation more terrifying than the full stop.
Compared to the allure of ellipsis or an enthusiastic exclamation mark (so beloved by we millennials that I have one tattooed on my wrist), the use of a full stop – be it at the end of an email, WhatsApp, or even this very sentence – is nothing short of intimidating.
Now it's official. This week linguistic experts have – rightly – claimed that the punctuation mark is viewed as a "sign of annoyance" by younger generations like myself who have grown up with phones in our hands. To us it's shorthand for "I'm so annoyed with you I'm going to send you this cold symbol of dread"; to anyone over 50 it's the only grammatically correct way to end a sentence.
Alas, this is just one of the many irritating inter-generational divides of our times...
Voicemails used to serve a purpose. Like in the Eighties when people had landlines and would arrive home to messages on their answering machines, and the funniest prank they could conjure up was to record themselves saying "Hello? Hello? Can you hear me?" before the beep. Possibly even in the Nineties when it cost 50c to send a text message.
But now? In a world of WhatsApp?
It's baffling. Yet baby boomers insist on waiting for unanswered calls to ring out (how they don't give up after the first two rings is beyond us), only to then wait even longer for the automated voice to explain how to leave a voicemail, before eventually recording an overly formal message that no one will ever hear.
Because no millennial has the time or inclination to listen to voicemails – let alone record one – when they could just read a message that says "Five mins late, soz!"
Doorbells are the new landlines: they're becoming so obsolete that the only people who use them are cold callers – or your mother. Because in 2020, there is really no need. Apps tell us when our Deliveroo is on the doorstep, or the package we're waiting for has arrived. And when our friends are outside, we'll know because they've already texted us saying 'here!' – meaning we can open the door at the exact moment of their arrival, and make life as seamless as possible.
But this modern etiquette seems to have bypassed boomers who eschew the common decency of a simple one-word message in favour of obstinately pressing a shrill doorbell – something so terrifying to millennials that there are actual studies showing this one little button can cause us fear and anxiety.
It's why my peers on Twitter are calling for an urgent solution: "Someone needs to make a doorbell that texts the person saying you've arrived. That way we don't even need to text it."
3. Watch live television
We millennials like TV just as much as boomers; they're not the only ones who got through lockdown with Normal People and The Nest. But unlike boomers, we don't know that the next episode is airing on One at 9pm this Sunday. We don't care. We probably don't even have a television set.
Why would we bother watching programmes live when we can just view them in our own time on a streaming service, which you can pause to go to the loo, get another snack, and binge watch – rather than arranging your social life around the listings in the Radio Times.
4. Assume anyone younger than them is a tech expert
Yes, we are more tech-savvy than you are. No, that does not mean we know why your laptop won't start. Yet for some reason, every boomer assumes that anyone in their 20s or 30s has the same tech knowledge as a Genius at the Apple store.
We don't. We might understand how the cloud works, but that doesn't mean we know how to take apart a motherboard. So please stop asking us to fix the family computer and just buy a new one.
5. Love the sound of their own phones
Most millennials I know don't use ringtones. We're so attuned to our phones that we can leave them on vibrate (even silent) and never miss a message.
In contrast, boomers love to keep their phones on loud. The second they get a call, a ringtone – personally selected rather than the standard one that comes with the phone – blares incessantly while they struggle to open their book-style leather phone case. But it's not just the ringtone that makes a noise. Oh no.
They love the sounds of their phones so much that they don't silence the keypad or Candy Crush. Which means anyone within earshot can hear them taking five minutes to compose a two-sentence message. Click click click.