…the role of wars in dealing the coup de grace to lingering customs is quite remarkable. Contemporary observers noted this development without comment or simply attributed it directly to the catastrophe. But war was less a cause of change than a precipitant of changes already under way. Edgar Morin makes precisely this point when he writes that in the parish of Plodémet “the war of 1914 accelerated and amplified most of the processes set off in 1880-1900.” Like the Great Revolution in peasant parlance, the Great War became a symbolic dividing line between what once was and what is, so that informants in a survey used terms like jadis and avant de guerre interchangeably. Yet wars are not watersheds for customs, but difficult times in which people are forced to focus on essential matters and come to see things differently. Many festive customs were not necessarily suspended by the Great War. In the countryside, mourning was almost as universal as hardship; two years for parents, one for siblings. There were few pigs to slaughter, no festive family meals, no public festivities. And after the war there was the great influenza epidemic. By 1919 the old customs were no longer part of people’s lives. Some were restored to their prewar prominence, but many were quietly forgotten.
That is from Eugen Weber’s classic Peasants into Frenchmen: The Modernization of Rural France, 1870-1914.