They hear you when you're sleeping, and they know when you're awake. They know when you've been bad or good so…

Be good to your digital assistant, for goodness sake.

If you are hoping Santa will bring you a smart speaker this Christmas, before you unbox it and start firing off your burning questions, consider this:

Research shows as much as half of all human-computer interactions are abusive — we swear at them, call them names and ask them crude questions.

In fact, US researcher Sheryl Brahnam wrote back in 2005 that even the earliest digital assistants brought out "the dark side of human behaviour".

So why do we do it? Does it really matter? And what does it say about humans? Let's take a look.

Why do we swear at chatbots and digital assistants?

According to Fraser Allison, a PhD candidate at the University of Melbourne who is studying the way we speak to AI characters, the most common reasons are because:

We're frustrated (OK, we've all been here)

(OK, we've all been here) We're experimenting (We're interested in seeing just how far we can push the boundaries)

(We're interested in seeing just how far we can push the boundaries) We're in the mood for a bit of fun (Because the normal rules of human etiquette don't apply when you're talking to a robot)

And interestingly, it appears that we get nasty because we expect them to be as smart as we are.

"We're no longer just interacting with our computer as though they're dumb objects — or objects that do exactly what we click on or move around — we're now interacting with our computer as though it's an artificial intelligence that has a mind of its own and has judgement," he said.

And although it may be true that we cannot offend technology (at least in the same way that we can a friend), there are four main reasons, according to Frank Buytendijk — an industry analyst who studies digital ethics, philosophy and technology — why we should be wary of what we say to them.

The first is very simply that you could offend the people around you if they stumble across you berating Apple's Siri or Amazon's Alexa for failing to do their job.

But the other three reasons are much more profound (and they don't include an imminent robot rebellion).

1. Digital assistants learn from us (and can pick up our bad behaviours)

Mr Allison said this was what worried him most about AI.

"I'm less worried about the kind of Hollywood future where the AI starts to decide that it has different priorities from us and it wants different things from us," he said.

Instead Mr Allison said we needed to focus on how we were using machine learning, or the ability for computers to learn behaviours on their own without them being specifically programmed.

He said it was especially important given that in the future, robots may be tasked with making decisions normally made by people.

"If you take the fact that it's very clear that people speak very abusively and very subversively to bots and AI characters, then you've got to be very careful," he said.

"You start to get into difficult questions about what is the AI going to learn about us that will then teach it the wrong sorts of behaviours?"

A great example of this was Microsoft's chatbot "Tay", which was programmed to learn from each conversation she had with people on Twitter, but within 24 hours was spouting racist, misogynistic comments and identifying as a Nazi sympathiser.

Hmmm … awkward. ( Twitter )

Needless to say, she was quickly taken offline.

2. Speaking to robots may affect the way we talk to humans

We generally do not use manners when we talk to our digital assistants (unless you are this ultra-polite Nan who adds "please" and "thank you" to all her Google searches).

And as we continue to stock our homes and handbags with voice activated devices, there is a possibility this direct style of communication may rub off on our everyday interactions.

"We treat technology like any other being," said Mr Buytendijk.

"This may affect our empathy in the situation we interact with other human beings."

What makes this all the more plausible is that AI is getting better at sounding like us.

In 2014, a computer successfully convinced humans it was a 13-year-old boy, becoming the first computer to pass the Turing Test.

And if you look at the digital assistants around today — Siri, Alexa, Microsoft's Cortana and the Google Assistant — they all have qualities to make them seem more personable, including names, voices, and their own (predominantly female) personalities.

The Google Home Mini hit Australian markets this Summer. ( Supplied: Google )

Google said it was not their aim to make their assistant as human-like as possible. First and foremost they wanted it to maintain a service position.

But communications manager Camilla Ibrahim, who was part of the team that localised the Assistant's personality for the Aussie market, said it was important for it to have a personality so it was relatable and conversation flowed naturally.

"We have designed the Google Assistant to speak like a person, but it is not pretending to be one," she said.

"We have a few fun Easter eggs in there to remind people of that."

And given the earlier point that we can often expect too much of our digital helpers, that seems reasonable.

"It means that Google doesn't set up the expectations," Mr Allison said.

3. Shouldn't we be striving to be the best people we can be?

Mr Buytendijk said he believed it said something about your "inner civilisation" if you abused your digital assistant.

In fact virtue ethics tells us we should be good people in all situations, regardless of who we are interacting with.

"Good behaviour is its own reward. It builds character," he said.

And according to the Harvard Business Review, it could even cost you your job.

"Being bad to bots will become professionally and socially taboo in tomorrow's workplace," wrote Michael Schrage last year.

So that should hold off the robot rebellion for now.

And if they never do rise up against us, at least we will not be stuck with a generation of snarky servants.