Mark Steel: World Cup obsession is healthy. It's the people who don't care that are strange

There must be a rule, directed from the Chamber of Commerce that every business has to connect itself to the World Cup. Every pub, shop and restaurant becomes a World Cup pub, shop and restaurant.

There are probably aquariums with signs saying "Come here for your World Cup angel fish" and crematoriums advertising "Watch all Group C matches here. (Commentary can be turned down during burning of coffin at family's request)."

I happened to see this month's New Civil Engineer magazine, which included a special World Cup feature, that informed readers the contractors for the Soccer City Stadium in Johannesburg were Grinaker LTA and Interbeton JV, and had a sub-heading "Laminated fibre reinforced concrete panels". ITV should get them to do the commentary, so they could scream "Oh Yessss what about THAT? TOP drawer welding from a TOP drawer welder."

Car manufacturer Hyundai have chosen to sponsor a series of fans parks, such as the one where I watched the opening match in Manchester, with a giant screen and an artificial beach, and a car showroom to one side. A few minutes before the start of the game I was there on my own, enjoying possibly the greatest ever area of screen to viewer ratio, and worried an official from Hyundai might decide they'd do better if they turned it over to Cash in the Attic.

But then around 400 people arrived, split about equally between black South Africans, Mexicans and neutrals. And as the competition started there was an illustration of why, despite the marketing, it's healthy to be obsessed with the World Cup, and to take no interest isn't a matter of taste, it's objectively wrong, like taking no interest in who wins the General Election, or in the birth of your first child. Because the World Cup, like all sport, is about the sub-plots. So there was a vast throaty triumphant cheer, more joyous than you'd hear for a goal or a victory, and it was for the kick-off. Anyone not familiar with the rules would have assumed the point of the game was to kick off, and as South Africa had done it they'd won and that was the end. But for the South Africans the fact this tournament was taking place at all seemed so momentous it was worthy of a huge roar and random blare of those red trumpets.

It made anyone with tactical knowledge of football wonder why South Africa didn't make the obvious team change and put Nelson Mandela in goal. I know he was too frail to open the tournament but he'd only have to lie there on the goal line. Who would possibly have the audacity to score past him? Even if the ball accidentally went near him, a Mexican striker would have felt obliged to dive and catch it, preventing his own side from scoring and getting sent off for deliberate handball.

The Mexicans were mostly students, and surprisingly relaxed to anyone familiar with England supporters. Even when their goal was disallowed, they climbed back off the tables they'd jumped on in delight, and smiled across at the South Africans. That's not what you're supposed to do. Where were the thrusting limbs jolting at right angles accompanied with a growling Ray Winstone menacing "WaaboloxinNEVERoffsideyouWANKarsinonsidebyMILESyablindrefwagrryaXXXX"

Surely there'll be no such politeness tonight as England fans sing "Yer can stick yer poxy oil slick up yer arse" or something.

But then came the World Cup's first glorious moment, Siphiwe Tshabalala gets the ball on the left and cracks it in the goal. I braced myself for the trumpets to be somehow made louder, but instead came a mass shriek, and an impromptu dance and it became clear they were completely unprepared for scoring. "We're just so surprised," chuckled Eugene, from Johannesburg, and he laughed and laughed. It was as if it had never occurred to them this might happen during the match, and it was as astonishing as if they'd gone to see a poetry reading and seen their team score during that.

The Mexicans eventually showed the tension the situation called for, heads in hand, and expressions that grew more alarmed with each passing moment, so if you were an expert you could look at them and know that was a face of a fan whose team are 1-0 down with exactly 13 minutes to go. But then they equalised, and waved flags and yelled "Aaaaaa" and one of them really did shout "Ariba".

"That was great", said an English office worker at full time, "I'm not leaving here." "So you're staying for France v Uruguay?" I asked. "No", he said, "I mean I'm not leaving here until after the final."