In real life, war is not a situation that anyone enjoys, but as a source of human drama, it's an ideal place for films to look for subject matter. War movies range in tone from the relatively uncomplicated adrenaline rush of military action movies to the more cerebral ambitions of realistic war movies and those with an anti-war agenda.
In the first half of the 20th century, war movies were most likely to be pure adventure, in which the good guys were on a quest to stop the nefarious aims of the bad guys. World War II, with its clear-cut good-vs-evil plot line, was a popular war to portray, but historical wars such as the American Civil War and the military campaigns against Native Americans in the American West got plenty of attention, too. In the 1980s, movies like the Rambo franchise and "Top Gun" gave the adventure treatment to the Cold War.
The 80s also saw the rise of the grittily realistic war movie. Oliver Stone's "Platoon" presented the Vietnam conflict that in no way glorified war, and Spielberg's "Saving Private Ryan" continued the new tradition.
America's war in the Middle East and Afghanistan after the turn of the century gave rise to a new type of war movie, one that strives for realism and adventure at the same time and takes a neutral stance on the conflict. "The Hurt Locker," "Zero Dark Thirty" and "Lone Survivor" do little to whitewash the reality of war, but they also stop short of making an anti-war statement.