It has caused rifts between friends, families and colleagues – not to mention members of Theresa May’s cabinet.
Now Brexit has brought two of the country’s best known sporting and broadcasting icons into open conflict.
In a barbed post, the cricketer-turned-commentator suggested the footballer-turned-pundit was breaching his employer’s guidelines on impartiality.
“Gary,” he wrote. “You are the face of BBC Sport. Please observe BBC editorial guidelines and keep your political views, whatever they are and whatever the subject, to yourself. I’d be sacked if I followed your example. Thanks.”
But Lineker, who played centre forward for Tottenham, Barcelona and England before pivoting to television, hit back, telling Aggers: “I’ll continue to tweet what I like and if folk disagree with me then so be it.”
He added he imagined Agnew, a pace bowler who appeared for Leicestershire and England, would not be concerned “if you agreed with me”.
Agnew, apparently aware of the old rule that there are no winners in a Twitter argument, responded with a simple thumbs-up emoji.
But after many users weighed in to say his post appeared to suggest he was a Brexiteer, the Test Match Special presenter tweeted to say he had voted Remain. “We lost,” he added.
It all followed a week in which Lineker sent a barrage of politicised tweets. “Extraordinary to watch us take our country back and rip it to shreds in the process,” he said in one.
In another he responded to his old England team mate Peter Shilton saying he liked Jacob Rees-Mogg by declaring: “What’s that old saying? You should never see a tweet from your heroes?”
The BBC’s editorial guidelines state that: “Impartiality lies at the heart of public service and is the core of the BBC’s commitment to its audiences.”
A spokesperson said: “Gary is not involved in any news or political output for the BBC and as such any expression of his personal political views does not affect the BBC’s impartiality.”