Harriet Walker: What those we despise can teach us

Another dangerous criminal bang to rights, and another candidate for witness protection. And the name of the plucky, public-spirited guardian angel who grassed up pub puncher Carlos Buller? CDWM to the initiated, or Come Dine With Me to all those hermits and troglodytes among you.

When Buller was caught on CCTV beating up a fellow drinker with his man-bag in Withington's Red Lion pub, police were unable to identify him. But when he finished second to last on the gastronomic reality show Come Dine With Me a year later – getting himself into a nasty spat with another contestant along the way – the rozzers located and pounced on the irascible interior decorator. He has since been given an eight-month suspended sentence, plus 150 hours of community service.

We whinge about the mindlessness, the 15 minutes of fame, the dumbing down, the insensitivity and the social barbarism of reality TV. But the genre has been misunderstood all this time. Why do we give these people airtime? Because it's community service in itself! Servicing our community of normal people, that is. You can't switch an idiot off in real life, but you can when they're on TV.

Fly-on-the-wall shows offer us a behind-the-scenes look at the peccadilloes of some of this country's emptiest and most unhinged minds; they expose and weed out the egoistic, pretentious, aspirational and downright dastardly from everyday circulation. In the case of Big Brother, for an entire summer. It means the rest of us can get on with our lives with ten fewer gobshites around to annoy us and with the knowledge that if we ever get a dinner invitation from a C Bruller Esq, we should turn it down. After all, without Big Brother, we'd never have known exactly how nasty "Nasty" Nick Bateman really was.

Even if you're the type of person who disdains BB and its genus (and you're not entirely wrong to do so), you may well still benefit from its existence – so don't be too gleeful that it's now over forever. Bear in mind the sort of people who apply to go on, not to mention those who actually make it into the house, or the kitchen, or the jungle or whatever the destination might be. It's the social equivalent of putting a teaspoon of jam at the end of the table so you can get on with your picnic free of wasps. It also means the sort of people who enjoy Big Brother will spend more time out of your way too.

Reality TV provides a welcome contrast to the honeyed nonsense that the modern era allows people to create and disseminate about themselves; the TV camera never lies. Facebook, Mysinglefriend.com, Craigslist: all are riddled with fraudulent claims and self-mythologising. If you're looking for a mate, perhaps reality TV is the best place to start the search – it's the only guaranteed warts and all representation any more. Let's face it, anyone who emerges from a bitchy TV programme smelling of roses has to be close to sainthood. Without reality shows there'd be no Ben Fogle, who is as much a force for good as Nick Bateman is of the darkside.

In fact, reality TV-esque scenarios for job applicants, potential flatshares, pub quiz teams and marriage doesn't seem such a bad idea, does it? The term is misleading because the reality is, we're actually after omniscience: what do they do behind our backs? What does she think about my new haircut, my signature risotto, that watercolour I insisted on hanging in the sitting room? Did he just pick his nose? Is that a wig? Does he really love me?

Reality TV answers the unanswerable questions, and people used to say that about religion. So before you decide it's gutter-level dross that sanctions gross indulgence on a shameful scale, just remember: you might have ended up living with that person if you hadn't watched them cutting their toenails into the cutlery drawer on national TV. Big Brother is watching out for you.

h.walker@independent.co.uk