Adam Persson thought everything would be fine when he left his dogs in his neighbour's care while he spent a couple of nights away for work.

Turns out they barked at night in their owner's absence.

The petsitter thought nothing of it, until they discovered an anonymous, handwritten letter in the mailbox.

It read:

Show some consideration for other people in the area and shut your f***ing dog[s] up you c*** head. You have been warned.

Needless to say, it left Mr Persson very worried.

The dogs were immediately moved, fearing someone would come to kill them.

The letter Mr Persson received over his dog. ( Supplied: Adam Persson )

"It's quite scary because you wonder are they going to poison them … if they going to follow through with these threats," Mr Persson said.

His situation was not an isolated case.

Earlier this week Brisbane woman Magenta Quinn received an unsigned note in her mailbox about her son, who has autism.

It said his "strange moaning and shouting" was disturbing the peace of the neighbourhood, and the letterwriter threatened to call the local council over the matter.

So why do people do this? Why not talk to their neighbour about any problems?

What drives someone to put either pen to paper or jump on their computer to bash out those angry paragraphs before slipping it into the neighbour's letterbox in the dead of night?

This note was left on a car windshield on the Sunshine Coast. ( Facebook )

The answer — they're trying to avoid any consequences, therapist Clinton Power says.

"When you're anonymous there's no consequences," Mr Power said.

"It happens online all the time and it's called online disinhibition effect. Basically people experience a lack of restraint when they're communicating and it's not in person.

"It kind of happens when there's anonymity, there's invisibility, there's no kind of consequences."

Lack of empathy when writing anonymous letters

Communicating in person compared to via a letter is also vastly different.

"When you're communicating with someone face to face there's so much more involved in body language and facial expressions, even just being in close proximity to other people," Mr Power said.

"So when all those are taken out, what happens is people can let out their anger or their frustration or nastiness without any bounds."

A Maryborough woman found this in her letterbox last year. ( Supplied )

There's also a lack of empathy when writing an anonymous letter.

"Empathy is a skill that happens in in-person relationships. It's a really important relationship skill," Mr Power said.

He has seen it himself.

"I'm in Facebook group of dog owners, and people in that group are saying people are leaving them nasty notes [about barking dogs], and the neighbour won't identify themselves," he said.

"Those notes are really aggressive and really nasty.

"Of course if you receive a note like that it's incredibly distressing, and it's even worse because you don't know who it is to sort it out and find a solution."

Talking to your neighbours Neighbourhood problems can be very upsetting and generate a lot of emotion, so when talking to them: Stay calm

Stay calm Explain how the problem is affecting you

Explain how the problem is affecting you Give your neighbour a chance to tell their side of the story

Give your neighbour a chance to tell their side of the story Be prepared to listen and let the other person know you are listening

Be prepared to listen and let the other person know you are listening Try working on a resolution together

Try working on a resolution together Take time to work on a solution and get it right Source: Queensland Government



Mr Power said it would be a different story if the person's identity was not a secret.

"If the person was outed or some way they could be identified, I'm sure they wouldn't be writing those things in the letter," he said.

He said those behind the letters may not be typically angry people, comparing it to those who have road rage.

"Road rage is never actually about the event that caused the rage," Mr Power said.

"It's just the catalyst, the trigger to the tip of the iceberg.

"Of course underneath the water is this huge area which is full of everything unrelated — stress from relationships, financial stresses, maybe dispute with the in-laws … all of that accumulates and then when that one precipitating event happens, the rage is focused on that one person."

'You're not as anonymous as you think'

Those trying to avoid consequences while raising an issue don't simply rely on late-night letterbox drops.

No surprise, it happens online constantly.

"We see it online — people creating fake accounts to say what they want and have no consequence," Mr Power said.

"And even if people rage at them there's no consequences for their employer, or their friends seeing what they're writing, there's no community backlash."

This letter went viral this week after it was shared online by the recipient. ( Supplied: Magenta Quinn )

Queensland University of Technology's senior lecturer in digital media, Dr Jason Sternberg, said people weren't as anonymous as they thought they are when it comes to online communication.

"If you're hiding behind a pseudonym or name you've created for yourself, people can track you down easily enough if they wanted to," he said.

"It's a real illusion that these keyboard warriors can remain hidden and jump online and say whatever they want about whoever they want with seeming impunity."