Eurovillageois may remember that the topcrat in question, Martin Selmayr, has greeted EU leaders like this before, notably Selmayr's ultimate boss, Mutti Merkel herself.
Cameron will doubtless take extra satisfaction from the trigonometrical undeniable fact that Selmayr bowed lower to the British PM than he did to Mutti.
By BM's calculation, a full 9 degrees.
Here's the proof: superimposed on each other, the freeze-frame moment when the German official's bow to each leader was at its nadir.
So why did Martin bow so low to Cameron?
A show of deference for the cameras?
A true sign of respect?
Or perhaps he was just back from the barbers, and wanted to show off his new hairdo...