Politicians do it well. Children do it poorly. Novelists and actors get paid to do it. Journalists must never do it. Lying is, let's face it, part of our DNA.
The scale of liars starts with the little white liar and dissembler and goes all the way up to the pathological liar.
Forgetting the smaller, sporadic lies at the bottom of the scale, what about those that lie constantly and lie big – why do they do it and how should we deal with them?
Trump: liar in chief
The world's most powerful man, Donald Trump, is a notorious liar.
In the 759 days since he took office, President Trump has made 8718 false or misleading claims. We know this because the Washington Post, in response to the frequency of his lies, made an ongoing Fact Checker database.
His response: he subverts it back onto the media, an Orwellian distortion that persuades it's them, not him, lying. Hence the unfortunate and dangerous rise of the "fake news" narrative.
The politics of lying
It's not just American politicians who are infamous for lying.
Worldwide, politics has become a profession so synonymous with untrustworthiness, it has entered into the realm of cliche.
Prime Minister Scott Morrison has been accused of lying about reaching our emissions reduction target. Deputy Prime Minister Michael McCormack has been accused of lying about that Medivac Bill, saying it'll result in rapists and murderers coming here.
Pathological vs compulsive
At this volume, we're talking about compulsive and pathological liars. The difference, says Lysn psychologist Tahnee Schulz, is nature vs nurture.
"For a pathological liar, lying is innate. There's a genetic predisposition, perhaps activated by trauma, personality disorder, or brain injury. Compulsive lying is more a learnt behaviour. A pathological liar is a compulsive liar but a compulsive liar isn't necessarily a pathological liar."
Why do they do it?
According to Schulz, behind a compulsive liar is a desire to be "accepted, connected, interesting or to get attention." Meanwhile, pathological liars will lie "sometimes for no purpose whatsoever."
They can both be charismatic, but a pathological liar can be dangerous; they have "no moral compass and no empathy" she says.
Compulsive liars may do so for, what they perceive to be, good reason.
"To conceal something in order to have acceptance, avoid punishment, or as a survival technique."
It isn't just the politicians. The New Yorker this month exposed best-selling author Dan Mallory's "trail of deceptions" including lying about having cancer, family members dying and falsifying qualifications from Oxford University.
It's something other writers have been caught out doing – Jeffrey Archer ended up in prison for it and James Frey ended up on Oprah for it. Closer to home, Belle Gibson also falsified cancer claims.
Trust your gut
Emmanuella Grace, a voice and body language expert, dispels myths about spotting a liar. "Sometimes liars look down and to the left, or avert eye contact. But a well practised liar may not give off these signals."
She says to look out for "micro facial expressions" - but they can occur faster than the mind can process. Combined with the pheromones which might pick up on fear and non-consistent inflections in the voice, she says you should use all this information to "trust how you feel in the moment" if something seems off.
Where to draw a line
It's hard to know whether to offer these people sympathy or castigation. People who lie this big and this often, Schulz says, are "by their very nature, disordered – they haven't found an elegant way to handle mental health in its own space."
But that doesn't mean they shouldn't be held accountable.
"Politicians' lies are wicked because they undermine democracy by denying the people the opportunity to give their informed consent," says Dr Simon Longstaff, Executive Director of the Ethics Centre.
"Nothing can be informed if it's is based on falsehood – made worse when calculated for political gain."
Confront them or nah?
Politicians aside (everyone I interviewed agreed they must always be called out) - should we go along with the lie despite our suspicion, so as not to worsen their affliction or prevent awkwardness? Or should we expose and confront them at the earliest opportunity, before it spirals out of their control?
Schulz says, in the case of pathological liars, exercise caution.
"They lack empathy so they're not going to feel bad – you need to keep yourself safe."
She advises that you "always follow your own value systems – don't just go along with the lies for the sake of not upsetting their mental health."
Proceed with caution
If you do decide to call them on it, go gentle, Schulz warns.
"Don't reduce your safety by calling out in a way that's aggressive or corners them. Discern if the lie streams from something bigger such as amnesia, anxiety or OCD.
"If not, go in with no rigid agenda and make informed decisions as you go along. Let them know this is a safe space. They'll give off signals to let you know if they have capacity to repair. If they're defensive, disconnected and lacking empathy, there's no mending of that friendship. Move away from them, cautiously."