Last week, I was mistakenly cc'd into an email from a PR, along with hundreds of other people (she had intended to BCC but an error meant that if anybody replied all it went to every single person on the mailing list).
It wasn't long before many of those copied in were responding, asking to be removed from the chain and calling out the woman on her mistake.
It only took one or two of these abrupt group mail-outs to drive home the error, but that didn't stop the flow of people adding their voice to the maelstrom in what - as someone finally pointed out - was rather a bullying matter.
This is just a very small flare-up of a condition I've come to know as "low-level London dickheadedness" (LLLD). If that expression sits uncomfortably with you, think of it instead as derision, or dismissiveness.
LLLD is the casual contempt for strangers that most people living in the capital exhibit on daily basis.
It's hurtful but not shocking, caustic but not criminal - an inane auto-response to urban living that falls somewhere between elbowing someone and nicking their chips.
And it's EVERYWHERE.
The dickhead within
LLLD is my term but any Londoner will recognise it instantly. It surrounds us all, as silent and insidious as an actual disease.
It's me, tutting at the tourist dawdling along a packed tube platform.
You rushing up the stairs so you don't have to be the last person to help the mum struggling with her pushchair.
The harassed-looking lady who barges past you in the lift every morning.
The city slicker who studiously avoids eye contact while queue-jumping you at the bar.
The cyclist who speeds through a red light and almost sends you flying, because his life is obviously more important than yours.
These acts are, of course, balanced by hundreds of other incredible and heroic ones; like the brother who died saving his sibling from a Tube train or the Good Samaritan who dived into the Thames to save a stranger.
But it doesn't negate the fact that LLLD lingers in the background of everyday life in London as a kind of undercurrent of contempt; more so than anywhere else in the UK.
Even the nice ones
No-one tells you about LLLD when you first move to the capital. It's just some subtle aspect of city life you're supposed to pick up, like using an Oyster or not saying hi to the bus driver.
It can come as a shock, especially if you (like me) come from the sticks, where everyone greets you with a smile - even if there are just two buses a week.
But after a few occasions of people being rude to you, you become familiar with the nuances of this cold, strange language.
You realise that no-one smiles or talks to each other on public transport unless they're weird. You acclimatise to the brusque dismissiveness. Before long, you're arming yourself with it; a modern-day London survival strategy.
This perhaps explains why even the nicest people are prone to LLLD.
We all know London is full of kind, creative and funny people - we say hi to them, work with them, support them, drink beer with them, hug them and sleep with them every day.
When I emailed round my (rational, lovely) colleagues on the topic, I received a flood of responses. Their malaise of resentment covered everything from slow-moving tourists to furniture dumping and talking about kale.
Perhaps with all this anger going on, it's no surprise that we delight in random acts of kindness - such as the Metro's good deed feed or a heart-lifting sign at Earls Court tube (below). Or that midnight hour on the Tube, when everyone's drunk enough to actually chat to one another without guile.
These moments show our common humanity, amid the relentless grind of city life. They remind us that we are nice people, beneath the layers of drive and defensiveness.
If the majority of us are good people but LLLD affects us all, how can we explain it?
Dr. Elle Boag, senior lecturer in Social Psychology at Birmingham City University, believes it's brought about by a combination of crowd-based selfishness and famous British reserve.
"The stakes are higher in the city," she tells me. "People earn more, work longer hours and are more competitive, because everything costs more. We have this concept of British 'niceness' but it's nonsense - in a crowd situation, we develop this skill of being really selfish.
"We're completely anonymous and free from constraint. Away from the eyes of friends or neighbours, we behave in a way that's completely self-serving. Intrinsically, we take what we can, where we can, even if that means stomping on a small child in the process."
And why is it peculiar to London, rather than say, Birmingham, Leeds or other big UK cities? Boag thinks the problem is exacerbated by a sardines effect.
"London is so densely packed with people, we're more likely to lose all sense of individual responsibility and accountability," she says. "We're all shoved together and we avoid eye contact so we don't have to acknowledge the basic humanity of ourselves or them."
And she says, LLLD is more pronounced in London compared to other international cities, because our Brit sense of reticence plays into a unique kind of passive aggression. We Londoners are less likely to call out selfish behaviour, so instead we keep our heads down and habituate it, as part of the norm.
"New York has it just as bad when it comes to aggressive commuters," she says. "But people there are much more vocal about it. They'll say if something's bothering them. In London, we're surrounded by self-centred people who are used to get whatever they want without question and push, push, push to get it.
"We might think 'what an arsehole', but we rarely say anything. Instead, we avoid it and develop a survival strategy that involves tutting and rolling our eyes.
"We'll go home and say 'you'll never guess what I saw on the bus today...' and the other person will respond, 'did you say anything?' - and we inevitably reply, 'Oh no, I wouldn't do THAT.' We weigh up the risk-cost benefits of getting involved, and decide it's not worth it."
There's really only one way to combat LLLD, says Boag - we need to reclaim an eroded sense of community.
"We're working all the time, so we don't know our neighbours," she says. "We need to work together take responsibility, rather than passing the buck. We need to break our silence and support each other when we see people behaving badly. If we consistently back each other up when we see selfish behaviour in strangers, those people will be forced to confront it - rather than just becoming defensive."
Recognise LLLD in yourself? Take a step back to think about other people. "It's usually our own fault when we get frustrated with people," she says. "Instead of huffing at people clogging up the escalators, remind yourself there's no need to be in such a rush. You should have left the house earlier.
"And if you see someone who needs help, take the time out to help them! Don't rely on staff, or hope someone else will deal with it. Just think that could be your mum or grandad struggling to get up the stairs.
"Don't feed into the negativity with more negativity of your own."
I don't want to get too Thought Of The Day about this.
But I think it's worth remembering that we Londoners can be lovely people, who are capable of brilliant things; we have free art, world-class hospitals, some of the best places to eat out in the world and the amazing camaraderie of events like the 2012 Olympics.
If only we could quell the LLLD that resides within us all, we'd be a kinder, more neighbourly place to live as well.
And that's definitely worth the effort of a repressed eye roll. Or even better, the risk of speaking out.
Words: Anna Brech, Photos: ThinkStock and Getty Images