The Great War brought about unthinkable cultural shifts in the 1920s that caused upheaval in all societies involved in the conflict.

Economic and political balances shook enormously. In Europe, empires crumbled, and new nations emerged from them. Extensive lands were destroyed (some of these lands would be unhealthy to live on up to these days). Economies first turned to war and then back to civil activities, sometimes with terrible disruptions. 

But what is perhaps more important is that there was a shift in the way people and governments understand their roles. 

After the Great War, most governments in the Western World started to take more responsibilities towards their citizens, and people started to expect their governments to take up those responsibilities. 
Some emergencies, like assistance to a vast number of disabled veterans and the consequent care for these people’s health, could not be expected to be taken up by any other but the nation they had fought on behalf of. A powerful sentiment emerged that because these soldiers had fought for their nations and had lost their health (physically or mentally), they were of course entitled to expect something in return. 

Expectations shifted greatly. Whereas before, governments were mostly expected to act on a global level and look after international relationships, now people expected their governments to do something for them. It was after the Great War that the first healthcare systems were devised, together with the first labour laws and working hours regulations. Contextually, participation in the political life of the nation was extended: in many countries, an extended number of men and often even some strata of the women population gained the right to vote. 

We take most of this for granted today, but it was a huge shift in the minds of many populations at the end of the Great War. 

How the Lost Generation lived the change

Despite their apparent listlessness, the Lost Generation was in fact the main player in all these changes.

• Government critics

Yes, they expected their government to take responsibility for the circumstances pressed on them. Veteran associations became very powerful in all combatant countries and pushed for help for all those who could no longer fend for themselves. 
However, although most nations shouldered the responsibility, actually giving that help was another matter. The costs were often too high. In fact, the entire post-war situation was so complex and based on new paradigms that most nations failed—or were perceived to fail. 
The Lost Generation was very critical towards them. 

• Rebellious at heart

The Great War caused rebellion in many parts of the world. In Russia, during the war, and after it in places as diverse as the US (1919 was a season of social and race riots), Germany (the 1919 revolution installed the first democracy ever in the country), Spain and Mexico, only to mention the most obvious suspects. 
The Lost Generation was naturally rebellious. They didn’t accept things as they were, and if this often resulted in disillusionment, sometimes it turned into rebellion. 

• Class relations

Bullets and shells didn’t make any difference between an aristocrat and a farmhand in the trenches. Helping each other was a must. Personal skills, more than social standing, became paramount. 
Trench warfare bizarrely promoted some sort of “egalitarianism” on the battlefields. 
The way men treated each other and even how men and women perceived each other showed this shift in their actions, became “inappropriate” once the world “went back to normal”.

Yet, nobody could erase the experience. 
That idea of egalitarianism could not be taken away from those people and caused indeed change in the after years. 
People were less willing to enter domestic work, for example, and opted for jobs in the new factory, which were better paid, demanded fewer hours of work, and made people more independent (this change, in particular, caused the fall of the aristocratic system in Great Britain). They were also less willing to accept race discrimination (as it happened in the US). 

Society’s fabric and structure were shaken – and not just in the main combatant countries. In many ways, the Lost Generation was less attached to societal norms than their parents.

• Gender relations

Together with the class-changing relations, gender relations also changed. 
Before the war, women were considered frail, delicate flowers in need of protection, and men the stoic, strong warriors who would protect them. 
The Great War turned these stereotypes on their head. Women took up jobs that had previously only been performed by men, both on the homefront and on the battlefields, where nurses and ambulance drivers faced the same violence and horrors as men. 
The Lost Generation was generally willing to acknowledge this. Mes accepted that women could be companions rather than wards (the 1920s New Woman was a vastly different woman than her mother), and women accepted that men could be vulnerable without being weak. 

As much as the Lost Generation thought they didn’t care abotu the future, they were indeed creating a new one. 

RESOURCES

USNews – World War I, the 1920s and Modern Cool
BBC – How World War One heralded social reforms
History Hit – 6 Ways World War One Transformed British Society