It's a neurosis, a disorder of the mind that makes it impossible for us to be at peace, and probably has a medical name like "False Wimbledon Annual Mental Expect-to-Win Unfounded Ridiculous Syndrome".
So every newspaper by law has to have headlines that say: "This could be Murray's year", every day. By Sunday the foreign pages will report: "Syrian rebel advance suggests this is the year for Murray", and the Home and Furnishings supplements will say: "Murray win may provide boost for sideboards." And it's all based on nonsense, so there are columns such as "I have a feeling Nadal may play the whole tournament lying down, which should play into Murray's hands. And Federer is a father now, so will probably cut holes in the net to make pretty shapes for his children which will get him disqualified."
They'll get more and more excited until the semi-final when they scream "A NATION PREPARES FOR UNRESTRAINED GLORIOUS MIGHTY INEVITABLE TRIUMPH", forgetting he still has to beat the best two players in the world ever, then if he loses, they'll call for an investigation into Fifa and tell us Murray has let the country down and ought to be scrubbed with thistles naked live on News at Ten for humiliating us like that. Maybe it's a feeling of entitlement, that seeing as we ran India for all that time, we should at least be allowed to win at tennis, even if, apart from Andy Murray, it would be quite hard to let a British player win if you wanted to, as you'd have to keep stopping to say: "No, it doesn't count if you pick it up and throw it."
Murray is by far the best British player for 70 years, and getting to semi-finals regularly is remarkable, especially as the British have done all they can to make things as difficult as possible for him. Because the thing about many people who tell you how much they love Britain is they only love one bit of it. The Wimbledon mob couldn't stand him because he wasn't like Tim Henman, who was the Daily Mail in shorts, and you felt that for every match he won, a penny would be knocked off the top rate of tax.
Murray is clearly much tougher, and doesn't fit into the Cliff Richard world of previous favourites, so he's been derided as being "dour", and you know he'd be more popular with that crowd if he put less effort into winning and played the first game of every set dressed as a flamingo. But also, we make it hard for most people to play the game at all. Most clubs are private and if you tried to just turn up and play, you might as well knock on the door at the House of Commons and say: "We couldn't nip in and run the country for a couple of hours, could we?"
But last year when I was in Spain, we did go to the town's club, with immaculate courts and umpire's ladders and everything, and for a few euros were allowed to stay as long as we liked. And I'm sure it's just coincidence, but in Spain thousands of people play and here they don't, and they've got 10 people in the top 100 and we've got Murray, and to learn to play he had to go to Spain.
We have public courts in parks, but they're becoming neglected, and in my local park there's an inviting sign that says "IF YOU DON'T PAY YOU DON'T PLAY", exuding all the charm of the Mafia. Maybe they'll put up another one that says "Give us your lolly or we'll serve and volley an opened-up brolly where you won't find it jolly."
Murray said he loved the final he won on Monday because, as it was delayed a day due to rain, it was open to the public. Whereas normally it's handed entirely to corporate hospitality, and the main attraction is the Veuve Clicquot champagne marquee.
It would be a stunning achievement if he did win Wimbledon, but you couldn't blame him if, at match point, he declared he'd become a Spanish citizen so we had to wait another 80 bloody years for a British winner anyway.