So I'm at a film screening last night and I see someone I know slightly. She's had her hair cut short. It looks good. I tell her so. Then I mumble something else before the lights go down. It's only later that I think to myself, did I really say, "But that's just me?"

I'm on the train when this notion occurs. Did I say that? Did she hear that? If she did, what did she think I meant? I imagine I had a vague notion of admitting that I like short hair as a rule. [1] But if you heard me say that what would you think? You'd think that saying, "I like your hair but that's just me," comes with the implicit unsaid proviso that no one else will. And that is not what I meant. Honest. [2]

But then I should know that I'm not very good at saying what I mean. My brain is a big gloopy bath of words and every time I go fishing for the right ones I seem to snag phrases that are either incoherent or, worse, the opposite of what I intend. Sometimes they have no bearing on what I intend. They're like a surrealist remix of intention.

When I get home I tell J what I did. She reassures me that I probably didn't say what I think I said. Then she comes up with half a dozen examples of times when I've said things I shouldn't.

"That's reassuring," I say. Now I'm really worried.

"Everyone does it," she says. "My mum does it all the time. When I ask my mum if my hair's a mess she says 'no, not really.' The not really negates the no, doesn't it?"

"Hmm," I say. I'm distracted. Memories of my past stupidities are flooding through me. "I've just remembered another time where I said the wrong thing. Over and above the times you've mentioned. Even thinking about it gives me the collywobbles."

"Was this when you told my sister …"

"No. It's not. We're not going there. Actually this was worse. It was in Edinburgh. I was working. We were doing a photoshoot in a bar. While the photographs were being taken I wandered away and saw a girl at the bar crying. So I asked her what was wrong and she told me she'd just learned that a friend had been killed in Australia. Or maybe it was America. I can't remember. In an accident.

"She was really upset and casting around for sympathetic words I came up with this. I genuinely said: "God, that's a killer."

"'That's a killer.' That must be the single-most inconsiderate, inappropriate, frankly offensive thing I could have said to her."

"It's not very clever," J agrees.

"Every so often I wake up imagining how much that girl hates me. At best, she'll think I'm that crass idiot who made a bad day even worse."

"Then again," J says, "that's what I think most days."

I say nothing. That, I decide, is my new policy.

[1] This goes back to 1982 and J's number two buzz cut.

[2] So if you're reading this P, your hair looks great. Full stop.