When I don't look good and I run into someone, I could tell them that I just won the Nobel prize for literature, but I know that as soon as they walk away the only thing they'd be thinking about is how I've gone downhill.

Sometimes, to make myself feel better, I'll think of a random celebrity. Gwyneth Paltrow, for instance. I've seen pictures of her in tracksuit bottoms, no make-up, hair unbrushed, and I can tell she's been caught on a day when she's not wanting to be seen. I empathise because the last thing I'd want is someone taking my photograph and having it end up in a magazine for all the world to see. But the empathy doesn't last long. Because I only wish I looked like her on her worst day. And if she's unhappy about it, she can always go home to her town house and soak in a tub of money.

The only thing worse than running into someone when I don't want to be seen is being seen by someone without knowing it. The other day, I got home and there was a message on my answering machine from a friend. He's someone I used to go out with and hadn't seen in a while. "I saw you," he said, "on 14th Street. I didn't say hello."

Hang on. If you see someone and avoid saying hello, you don't call them afterwards to tell them. What good does that do? Essentially, he's saying: "I saw you, you didn't see me, I win."

I called him back. "Why didn't you say hello?" I asked. He told me he was running late for an appointment. Sure he was. But I had a more important issue to raise. I had a horrible feeling he saw me on the way back from the gym. So I asked: "What was I wearing?"

He told me I was wearing a sweatshirt, and I felt myself sinking. There's just something so wrong ?about being seen on the way back from the gym, looking sweaty and gross, ?and then finding out about it. So I ?did the only rational thing I could ?think of. I lied. "That wasn't me," I said.

He was silent. "Really? It ?looked just like you."

Nope, I said. I don't think so. "Really?" he repeated. "You weren't wearing a sweatshirt and race-walking on 14th Street yesterday?"

Race-walking? Now I sounded ?like someone who goes to a Jazzercize class in Florida. I told him I might ?have been on 14th Street and I ?might have been wearing a sweatshirt, but I certainly wasn't race-walking.

"Really?" he said, for the third time, "Are you sure?" I replied: "Yes. I'm sure." Now I was getting annoyed. He sounded like he didn't believe me. So what if I was lying? He didn't know that.

"Where were you?" I asked. He ?told me he was across the street. ?I pointed out that if he was across the street, it's not as though he got a good look. After a few minutes of convincing him that it was a case of mistaken identity, he finally relented. Then ?he said: "Whoever it was, she looked pretty. But I guess it wasn't you."