Public opinion in Austria-Hungary was largely supportive of the war. The assassination of Archduke Franz Ferdinand, the heir to the throne, had provoked outrage and a desire for revenge against Serbia. Many Austrians believed that Serbia was a threat to the stability of the empire, and that war was necessary to preserve the monarchy.
Germany
In Germany, public opinion was also largely supportive of the war. The German people had been led to believe that the war was defensive, and that Germany was fighting for its survival against a hostile alliance of Russia, France, and Britain. Many Germans were also motivated by a sense of patriotism and a belief in the superiority of German culture.
France
In France, public opinion was more mixed. Some Frenchmen supported the war as a way to avenge the German invasion of 1870 and to recover the lost province of Alsace-Lorraine. Others were opposed to the war, fearing that it would lead to a bloodbath and that France would be defeated.
Britain
In Britain, public opinion was also mixed. Some Britons supported the war as a way to defend Belgium, which had been invaded by Germany, and to prevent Germany from becoming too powerful. Others were opposed to the war, fearing that it would lead to a long and bloody struggle.
Overall, public opinion in the countries involved in World War I was complex and varied. While some people supported the war, others opposed it. The reasons for these different opinions were many and varied, and included factors such as nationalism, patriotism, fear, and a desire for revenge.