It happens: sometimes that filter in our head bursts and we say too much of what we’re thinking and someone gets hurt. Tell us about a time you or someone you know said something that they immediately regretted.

 We were talking amiably, and my companion – I had met him on the same café terrace in Neukölln where I have breakfast most days – was turning out to be a knowledgable Berliner.

He had a good recollection of his youth in East Berlin, and was telling me lovely stories of his schooldays, and his love of football. He was a charming “raconteur”.

As I looked around at the gracious locals walking to their business, I became conscious that my companion was observing me. I smiled, as we older men do, when we are considering friendship, without yet being committed to anything.

We had not really introduced ourselves. And then he started the sentence: “I must tell you, doctor Faust…”

Immediately the fraudster knew that he had unmasked himself. My name is not Faust, and I am no doctor, but he considers his possible preys, all of us, as the same and one person. I stood up, towering above the little man, well, the creature he had adopted the shape of.

“Out of sight,” I said in a tone that did not expect any reply, “Get out of here, go, now!” And he did.