Interruptions by waiters have a deadly effect on anecdotes; they are always perfectly timed to ruin the punch-line. The chatter and laughter of fellow diners constitute other hazards.
A regular star of the tapes was a man who dined nightly in one of my regular venues. I came to admire his style and courage: he was dandyish - macaronic, the Victorians would have said - and completely disregarded a speech impediment which made his conversation resound like the braying of a donkey.
The memory of those days was revived last week when I had dinner with Alex Salmond, who renounced the SNP leadership last year but has since been persuaded to lead the parliamentary party at Westminster. I could not shake him from his assertion that he had given up the leadership because he had done it for 10 years, quite long enough.
He has naturally been mocked for what was seen as apostasy. He has been accused of turning his back on the Parliament he had helped to found.
Last week he argued that it was practical politics. His continued presence at Holyrood, he felt, would cramp the style of his successor, John Swinney, no matter how he tried to make himself unobtrusive. And the new SNP intake to Westminster would be a fresh generation needing experienced leadership.
I am unable to bring you direct quotation of his remarks. On Friday morning I slipped the tape into the car's cassette player. The playback began with laughter from a nearby table. Then as Alex answered my first question a waiter asked thunderously: 'Who's having the spinach?' At this point the tape jammed and this morning remains stuck fast.
But I left the table convinced that there was no hidden agenda behind his decision. I did detect a certain bitterness about some of the groundless rumours circulated about him during the Holyrood election campaign. He suspected they had been put about by his opponents.
And I also sensed a residue of rancour about the factional squabbling, attributed by commentators to the Sillarsites (though Jim Sillars himself rejects the charge), with which he had to deal towards the end of the leadership.
Another and perhaps even greater source of unhappiness was the vicious treatment he had received from sections of the Scottish press during the Holyrood campaign. Until relatively recently the native newspapers have been largely fair-minded (a tradition maintained by the Herald ). But two factors have changed the landscape. First, the English titles now in the marketplace, notably the Sun and the Daily Mail, freely mix their reporting with prejudice. Among the indigenous titles, the Scotsman has become an opinionated pamphlet under the Barclay Brothers and Andrew Neil, its headlines dripping with attitude, either anti-Labour or Europhobic.
Yet, you might say with Truman, a class politician has to be able to stand the heat. This is no game for pygmies but a gigantomachy, a titanic struggle for supremacy. The SNP is a slightly different case. In major parties, taking time out might have a fatal effect on a career; rivals would simply come jostling through.
By contrast Salmond can afford to stop and smell the flowers along the way. I suspect he has not gone for good. Guile and experience are not exactly in plentiful supply in the SNP and there will inevitably be a dearth of Westminster expertise. But above all I came to the conclusion that Salmond was suffering a little from ennui. And the remedy proposed by his doctor to Buchan's Richard Hannay - steal a horse in a part of the world where to do so is a capital offence - is hardly an option for man who has led the SNP always along the paths of reason.