It feels as if the world has gone mad lately. Everyone's angry about everything all the time. Not just a bit cross, but palpably, blisteringly furious, and any spark can set it off.
Some would blame the recession - but it can't be that, because we've been poor before, much poorer than we are right now, and we didn't go utterly crazy as a result. Though perhaps the only reason we managed to stay sane back then was because we didn't have social media.
In the same way there's a theory that no two countries ever go to war when both have a McDonald's restaurant, it may well be discovered in future that a country's mental well-being is directly linked to the proportion of its population which is on Twitter. The more tweeters there are, the more messed up a country becomes.
Because there's no getting away from it. Tweeting does strange things to people.
There was another illustration of that last week when, after the awful crash in Glasgow which left six people dead, a young man in England posted a tasteless joke about it.
What was worrying was not the joke; sick humour will always be with us. Far more disturbing was the reaction which followed, as the man became the target of other social media users, who not only circulated his photograph and address online, but wished that he would "get done in", or that someone would "shove a knife up your fat a*******", or "smack him with a cricket bat".
Curiously, it was the joker himself who ended up being investigated by police, rather than those calling for his murder. The result is that another young person's life has potentially been ruined for one small act of stupidity, but no one cares because they're too filled with righteous anger to see their own intolerance.
Of course, there are always limits to free speech, and it's extraordinary how so many still don't seem to understand that things said online are public not private statements.
Otherwise normal people, who presumably hold down respectable jobs and have friends and families, suddenly become monsters when they go online, sending hundreds of abusive and defamatory tweets to, or about, other people. Here they are, with all this astonishing technology at their fingertips, and all they can think to do with it is to act like raging morons.
That each tweet must be shorter than 140 characters probably encourages them to do so, by forcing users to reduce their thoughts to the crudest caricatures. Subtlety dies from lack of space.
Add alcohol to the equation, and trouble's bound to follow. People may say hateful things when drunk, but they don't usually have a megaphone on hand through which to shout, and Twitter is the ultimate megaphone. There's no filter. Just type, then send.
The young woman jailed in England for sending abusive messages to feminist campaigner Caroline Criado-Perez had generally been drinking when she lost the lost the run of herself.
In fact, she even admitted that she'd done it again one night after being released. She came in from the pub, turned on the laptop, and was soon embroiled in a spat with some randomer who'd annoyed her, presumably involving LOTS OF CAPITAL LETTERS, because that's a feature of these exchanges too.
In the past, when you rolled home the worse for wear from the pub in the early hours, the most embarrassing thing you could do was drunk text your ex. Now the whole world beckons on Twitter. It's like having your own private media organisation. It's compulsive.
There have been studies done on this, which suggest there's something addictive about social media. Each time someone "likes" a post on Facebook, or retweets your comment on Twitter, it's the equivalent of a little shot of adrenalin into your bloodstream. You feel empowered and validated. You become like Sally Field, gushing as she wins an Oscar: "You like me, right now, you really like me."
Or hate you. It's all the same to the needy. Each provides a quasi-narcotic kick of delight.
And when that addiction goes political, it makes for an even more toxic cocktail.
Eoghan Harris recently wrote a prescient piece on groupthink, in which he described the process whereby mobs begin to think and act as one person, and outsiders are demonised and hounded.
That's as near perfect a description of Twitter as it's possible to find, and this year was flanked by two textbook examples.
The first was Pantigate, when anyone who expressed the slightest reservations about same-sex marriage was howled down as a homophobe and pelted with hashtags and slogans until they either submitted to the mob or were driven offline.
The second was the mass trolling of IRA rape victim Mairia Cahill. Some of that came from pathetic individuals, drinking too much, their lives out of control, who are able to misuse Twitter and Facebook and convince themselves that sending hundreds of messages insulting a rape victim counts as iconoclasm or, more laughably, fearless investigative journalism. These are on a level with the misfits who think it's funny to taunt Madeleine McCann's parents about their missing child.
Far too much of it, however, was cruelly organised by supporters of Sinn Fein/IRA, which, like the hard left in general, have a social media presence hugely out of proportion to its actual support in the country, which it uses to intimidate opponents into silence.
Consider it a lesson in what life will be like if they ever do get an actual, as opposed to a Twitter, majority.
In their hands, social media has become a plaything of the authoritarian left, as they casually disseminate libels which, were they repeated in print, would have those who wrote them fired whilst likely bankrupting any publication foolish enough to reprint the lies. On social media, it doesn't matter, because there are no consequences.
Unlike mainstream media, Twitter doesn't accept responsibility for what its users say and do, and you can't sue every paranoid loser with a smartphone and nothing better to do with his time than use it to stalk those against whom he has a grudge. The lack of consequences has coarsened public discourse and brought something ugly into the political landscape.
There's nothing that can be done about that. Censorship doesn't work online, and, even if it did, it would be wrong to throw away the anarchic, democratic openness of social media simply in order to put manners on a few socially inadequate dingbats. Whether there's any point engaging with it is the real question.
Increasingly it's hard to escape the conclusion that the lunatics have taken over the asylum and should be left to squat there in their own filth. They may mistake it for the real world, but that doesn't mean the rest of us have to share the same sad delusion.