: Sorry, I'll have to shout this: Great party]

WHAT are parties for? I ask myself this question after the usual round of Christmas and (ouch . . . pass the Nurofen, please) new year celebrations.

They are not for making conversation, since doing so is impossible in the teeth of a sheer, north-face-of-the-Eiger wall of sound. In snow-storms it's called snow-blindness; at parties it's word-deafness. In surroundings of this chest-rattling volume, speech can be heard only if bellowed directly into the ear of the recipient. Failing this, one perfects a detailed repertoire of smiles, moues and judiciously balanced uncertainties by way of reply, which the experienced party conversationalist learns to interpret in as much detail as a seven-sentence paragraph. All the same, it can hardly be called the ideal setting for wit or debate.

Parties are not for making important new contacts, since on arrival one invariably heads straight for the people one already knows. Few things are worse than turning up, coiffed and painted and scented and dressed in one's best, only to discover that one doesn't know a single person there. This happened to me in the week before Christmas, and I kept going bravely for a while on the advice I was given long ago by a veteran party-goer.

'Pretend you are an anthropologist, studying the mating rituals of a strange tribe. Observe how they use eye contact, gesture, and the exchange of favours - the fetching of drinks, the granting of smiles - to establish dominance and attraction.

'After a while, someone will be so intrigued by your rapt attention that they will come and ask you what you're doing: and after that you're well away]'

Ten minutes of undivided raptness and nobody came near me. Jolly humiliating.

Parties are not for looking at paintings, as anyone who has been to a private view knows, or for talking about literature, as anyone who has been to a book launch can attest. They are not for celebrating birthdays, as any furious six-year-old demonstrates when it ends the afternoon drumming its heels in a tantrum. The presents disappearing through the front door clutched in the paws of the undeserving little guests ('Vey're not my fwends] I hate vem]') are always superior to the presents received.

Parties are not for enjoying good food and drink, since nobody ever serves their best wine at a party, or any food more recherche than canapes, a form of nourishment designed to be eaten without implements while standing, talking and holding a glass in the other hand. (The near-extinction of smoking has finally made it possible to manage without a third hand.)

Surely this leaves only two things to justify parties: looking at people, and getting intoxicated on a scale from tiddly (my mother's word) to rat-arsed (my son's). Or, for those under 10 years old, being sick after too many jellies and a tantrum.

Why, in that case, do I continue to look forward to parties with all the fevered anticipation of a boarding school girl getting her quarterly glimpse of the opposite sex? Why do I spend hours searching my wardrobe for the magical garment that will transform me into the belle of the ball? Why do I peer minutely into the mirror so as to apply the perfect sweep of eyeliner, the ideal load of mascara, the irresistible pout of lipstick? Why do I take a taxi, thus preserving the illusion for as long as possible, unsullied by tube trains or bus queues?

It must be because parties are the final decadent flowering of the social ordeal by which the hormonally active seek their genetically matched opposite number.

Parties still provide the best opportunity for meeting and feeling that stupendous leap of recognition, that moment which justifies all the preparation; the One-Enchanted-Evening moment, the Across-A-Crowded-Room sensation.

Can there be a more thrilling millisecond in the whole year than the locking of eyes, the first tentative, 'Are you here with anyone?', followed by 'Oh but I adore Mahler]' (or narrow boats, or broad beans, or whatever unlikely fetish has just been confessed) right down to the final, hours-later bliss of 'Can I give you a lift home?' There's nothing like it, and while it may only happen once in every 100 parties, it's why one puts up with the other 99.

Parties, as Shaw observed of marriage, represent the triumph of hope over experience. Long may they last.