It's there, somewhere in the system. But nobody really has a clue where.
Well a cynic might say that's what the postal service would want us to believe.
Except occasionally there really is evidence that our sometimes tried and tested patience is not misplaced.
Such is the case of a postcard, according to the regional daily La Dépêche du Midi, sent by a certain Monsieur Le Petit in July.
He was holidaying in the southwestern village of Praz-sur-Arly and wanted to say a simple "hello" to his friends, Madame et Monsieur Bigot, who were renting a gite just over 630 kilometres away in the southwestern village of Saint-Martin-de-Vers.
"The area is very beautiful," wrote M Le Petit.
"See you soon. Enjoy your holiday and have a good rest."
The card plopped through the letter box of Charles Dardenne, the farmer who owns the gite, at the end of August.
But the Bigots weren't there.
And with good cause.
Because the card was postmarked July, 1970.
Yes it had taken a mere 41 years to reach its destination.
Dardenne, when interviewed by the paper for Thursday's edition said he was thinking about tracking down the Bigot family and M Le Petit to find out what had happened to them.
Clearly though, the postcard had other thoughts, because a day later, when contacted by Agence France Presse, the farmer said it had gone missing - again.
"It's a mystery, but I cannot find it," he said.
"Perhaps it'll make a reappearance in another 41 year, but I won't be around to see it," he added.