What were the social trends during WWII?
Check out the first link below to get a feel for what family life was like during the war (click on simulation). There were so many big social changes -women went to work outside the home, which had never happened before, and lead to a major revolution in who works in the American family; people were encouraged to pay off debt and save, particularly by buying war bonds. Many things were rationed, leading to shorter skirts (to save fabric), recipe development and "Victory gardens" to stretch scarce food and work around shortages of meat, butter, and sugar, and overall creativity to make things last.
Music, books, and movies tended toward either a light-hearted tone or patriotic. A big push of government was to encourage people to keep secrets, so as not to betray any information about troop placement or movements to the enemy. Letters from soldiers were heavily censored, and workers employed in defense industries were scrutinized. The US even incarcerated people of Japanese decent just to make sure they weren't spies. This drive for secrecy led to paranoia which was a factor in the "Cold War" that occurreed for the two decades after WWII.
If you are talking about the social trend in the United States during this war, the major trend was towards austerity. People all over the US made various sorts of sacrifices to help win the war.
Of course, the most obvious sacrifices were those made by the soldiers. However, I assume that you are asking about the "homefront." There, sacrifices tended to be more economic and social. People gave up their pleasures for the sake of the war. Little to no driving for leisure happened. People had to eat fewer fancy foods because of rationing. Luxuries like silk were very hard to obtain. Because of this need for austerity, a major social trend in the US during this war was the prevalence of sacrifice.