Fear was caused in World War 1 in numerous ways. The brutality of trench warfare and the use of new and deadly weapons such as machine guns, tanks, and chemical weapons created an atmosphere of constant danger and uncertainty. The mobilization of millions of soldiers and the high casualty rates also contributed to fear. Propaganda was used to manipulate public opinion and stoke fear and hatred of the enemy. The psychological impact of the war was immense, and it left a lasting legacy of trauma and suffering for those who lived through it. Fear was a major factor in the war, affecting all who lived through it.