So far, so good.
But here comes an affable fellow in a grey suit with a round face, rimless specs, receding hair and a striped tie.
Who on earth can he be? He is an utterly generic middle-aged chap.
For all you know, he could have wandered in from the dry-cleaning conference next door.
But - horrors! - he seems to know exactly who you are. "G'day, Chancellor!" he cries.
And what can you do but arrange your features into a beaming smile of feigned recognition and advance, hand outstretched?
Poor Angela Merkel, no wonder she was driven to consult her briefing notes not once but several times during her meeting with Scott Morrison, the seventh Prime Minister of Australia (if you count Kevin Rudd's two premierships) during her chancellorship.
Just the one quick look - or, better still, a glance at her notes before their encounter beneath the beady scrutiny of the press cameras - might have been more tactful.
But with the Christmas party season approaching, who can blame her?
Just as there are people who tackle cryptic crosswords or quadratic equations with bold confidence, there are people who like nothing better than to surge into a packed party of yelling guests in sparkly festivewear, greeting with enthusiasm people whom they have not seen since last December, and effortlessly remembering not only their names, but those of their spouse, children and family pet ("How is Pongo? Did he get over his kennel cough?").
Meanwhile, the rest of us cling desperately to neutral pronouns and open-ended questions: "And what are you up to these days?" (If the answer is, "Oh, you know. Still singing a bit", you have just failed to recognise Ed Sheeran.)
Some of the office Christmas parties I annually attend try to help their hapless guests by providing us with name badges, thus ensuring that we spend the entire bash with our gaze riveted upon our fellow guests' upper torsos, rather than their faces.
The fact is, some of us are designed by nature to mingle, and some are not.
In my case, a combination of extreme short sight and a tendency to daydream mean that I struggle to recognise even the people I know best, when encountering them out of context.
My partner is invariably disconcerted by the blank and vaguely hostile gaze I turn on him when we meet unexpectedly in the street. But then his dear old phiz swims into focus, and how pleased I am to see that it is him, rather than some acquaintance whose name I have wince-makingly forgotten.
Which is, I am sure, just how Merkel feels on sighting the familiar features of Vladimir Putin across a crowded summit.
