At some point in the last decade the aspiration to “switch off” on holiday ceased to be a metaphor. Disengaging from digital devices is good for peace of mind throughout the year, but the season of goodwill is especially enhanced by keeping off the networks where ill will breeds.

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Was social media nastier in 2017 than in 2016? Maybe not, but nor has it followed a trajectory towards civility and tolerance – not where politics is debated. That word itself is moot. Debate implies exchanges of opinion, arranged on commonly agreed platforms of fact. There isn’t much room for that when the prevailing styles are pulpit and pillory.

There is humour, too. When Twitter isn’t making me cross, it often makes me laugh. But then the target for ridicule is often some political inanity or offensive distortion of truth. So I still taste anger inside the sugar coating of smug satire. This is not a nutritious mental diet.

Why stick with it? Twitter efficiently aggregates news from multiple sources. It still serves up things I want to read among all the things I wish I could unsee. Social media is also an early-warning signal for political trends. Last month, a minor vote in parliament on animal welfare sparked a wildfire of controversy, prompting grovelling Tory pledges to ever more be kind to quadrupeds. Facebook was aflame for days before MPs realised what was going on.

Ideally, there would be filters to isolate good information and judicious analysis from the shrieking din. In reality, they are inseparable. Often, the hysterical pitch of reaction to a story is the story. The Tories never had a policy of rejecting animal sentience, but the ferocious response to a mis-reported, mythologised enactment of that policy made it a thing.

Anger is useful in politics as a spur to action against injustice, corruption, misrule. It is toxic as a gateway to raw hatred

Twitter hangs on Donald Trump’s every word partly to glean insight into the mind of the president, but also because each tweet triggers a cascade of fury that energises the network. Trump is angry. Liberals are angry back at him. Conservatives are angry with liberals. In the UK, remainers are angry because they lost in 2016 and are still losing. Leavers are angry because they won and the other side won’t celebrate with them. For some, anger becomes the cause. Giving it up would be a form of surrender. There is a reason why converts to the dark side of the Force in Star Wars are encouraged to cultivate their hatred – to feel it as a source of power. It has sometimes felt this year that British politics is going over to the dark side.

Rage is contagious. It spreads from one sweaty digital crevice to the next, like a fungal infection. It itches like one too. When sitting at the keyboard, it is difficult to perceive wrongness without wanting to scratch it with a caustic retort. But that provides no sustained relief. One side’s scratch is the other side’s itch.

And so the cycle of provocation continues. It is hardwired into the network. We customise our news feeds to partisan taste, digging information trenches along the contours of our bias. Then we hurl pointless barrages of disbelief at the enemy trench. This has become part of the media business model, what has been called the “outrage economy”.

Extremes of opinion cause spikes in web traffic, which suits publishers and platforms. In the currency of clicks, an inflammatory, racist article by Katie Hopkins, for example, yields a double payoff. It is shared by people who agree and by people who violently disagree. Mercifully, the Hopkins bubble burst this year. (Twitter aside, she is currently without a regular media outlet.) But other bubbles will inflate as long as there are commercial incentives to keep everyone’s blood boiling, and insufficient social or political pressure to lower the temperature.

Facebook Twitter Pinterest Tributes to the MP Jo Cox after a far-right extremist was found guilty of shooting and stabbing her to death days before the Brexit vote. Photograph: Ben Stansall/AFP/Getty Images

An outrage economy is lucrative only in an outraged society. Once stoked, the anger becomes self-sustaining, addictive. There is a physiological gratification in rage – a primitive adrenal response that overrides more sophisticated emotions. It can be perversely comforting. Politicised anger feels virtuous. It is the kick of moral purpose, but conveniently stripped of any obligation to consider nuance or alternative perspectives. Hatred of a proposition, or a party, removes interest in understanding why others like it. Self-righteous anger is an excuse not to even try to persuade. St Augustine’s invitation to “love the sinner, hate the sin” does not have much purchase on Twitter.

Addicts develop tolerance to the effects of their drug, requiring ever stronger doses. In this context, I find the prevalence of violent metaphor across the political spectrum disturbing. There is a vast gulf that separates the Brexit ultra’s denunciation of traitors and the decision by a far-right acolyte to murder an MP. But there is also a bridge between them: a chain of association that eases the journey in a disturbed mind from stewing in hatred of an imagined enemy to seeking vengeance.

The digital Desmoulins of the Corbyn revolution rarely explain who is to be smashed, and with what tools

But violence can be more subtly seeded in political language. It is common around the grassroots of Labour to hear calls for the whole capitalist system to be smashed, usually from young activists who have never experienced the trauma of living through a system in ruins. The neo-Bolshevik rallying cry sounds romantic until you consider that “the system” is actually a set of institutions run by people. The digital Desmoulins of the Corbyn revolution rarely explain who is to be smashed, and with what tools, if it is all to be done on a scale to bring the whole edifice down.

The urge to radical demolition is born partly of despair when gradual reform feels inadequate to effect social change. But it expresses the cyclical impatience that grips the activist temperament after periods of technocratic consensus. Clive James once observed this habit in fidgety intellectuals: “For them, a political system which has attained a condition of vibrating stasis provides an insufficient resonance. Briefly, they find it boring. Bored, they play with fire.”

Anger is useful in politics as a spur to action against injustice, corruption, misrule. But as a gateway to raw hatred, stoking an appetite for retribution, it is toxic. The distinction between those modes is lost in the riotous rhetoric of online dispute, which increasingly permeates the world offline. Switching off devices isn’t a solution. But it is a way to avoid – if just for a few days – being part of the problem; to avoid the call of the dark side.

• Rafael Behr is a Guardian columnist