Alcohol poisoning does exist. You can catch germs off a dirty glass. Thank goodness it's Monday morning so the horror of a hangover from Saturday night is finally beginning to recede.

"I never get hangovers," says my sister blithely. "Neither did I when I was 21," I snarl back down the phone. "Just wait. By the age of 24 one glass too many of white wine can make you wake up at 4.30 with a blinding headache, raging thirst and a need for paracetamol. It happens to all of us."

I can tell she doesn't believe me. In my mid 20s I have developed a sensible attitude to parties. Before I go I make the following resolve: I am only going to drink two glasses of wine. I will behave in a mature and sensible fashion.

Three hours later when I'm reeling around in some pub, dancing with more enthusiasm than skill, there is always a minute's epiphany: I know I am going to feel terrible tomorrow. Then I have another drink and suddenly I'm OK again.

In your 20s parties suddenly divide. There are the mature, engagement parties (held in first-time buyer flats, with discreet nibbles and white wine). And then there are the pseudo-student parties (rented places, lots of beer, red wine and cigarettes and Abba played very loudly). But it doesn't matter which one it is; I end up with a hangover.

There's always the weirdest coincidences at twentysomething parties. You are blithely telling tales of college days, safe in the knowledge that your host went to a university at the other end of the country. But then you end a story by saying, "Anyway Helen turned out to be a real cow; we were well out of it ... Her surname? Yes, it probably is the same person as your boyfriend's flatmate. Hahaha."

Still, it could be worse. I had just started going out with an absent- minded intellectual when we went to one of these studenty parties. He immediately met Paul, a friend of his, and launched into a long anecdote. I shifted from foot to foot. Eventually he realised.

"Oh sorry I've been really rude," he said. "Yasmin, this is Paul. Paul, this is Yasmin."

"Glenda. My name is Glenda," I said through gritted teeth. Yasmin was a friend of mine.

He did apologise repeatedly for his vagueness. Still I ended up with a hangover. Rather than him.