Part of me believes Katara should have killed the man who killed her mother, mainly because what he did to her and many other Water Tribe members was despicable and irredeemable. But at the same time, I understand that Katara's desire for revenge was making her angry and bitter, especially to Zuko, turning her into somewhat of a bitch. I suppose that killing the guy, while it would've felt satisfying in the short term, wouldn't have relieved the bitterness inside her.

I think my "Gray Area" of killing has always been the Russian Army's treatment of Nazi Germany in COD: World at War. The main message of the game was how destructive the war was, and how it drove all sides, even the Allies, to do things we'd find despicable. 

Throughout the Russian campaign, you (as Dimitri) and your comrade Reznov survived the Battle of Stalingrad, where thousands of your friends were killed by the invading Nazis. Your first mission involves the two of you assassinating the German commander Gen. Amsel, setting off a long chain of events of getting revenge on the Nazis.

In later missions, the Soviets pushed the Germans all the way to Berlin. Along the way, you see Reznov and other Russians brutally executing surrendering Germans, and are even encouraged to take part in it yourself. Another character, Chernov, often objects to killing unarmed men, but is constantly shut down by Reznov.

Each time I play it, I find myself torn on who I agree with (which I think was the intent of the story). On one hand, I sympathize with Reznov on wanting revenge because of what the Nazis did to him. But on the other, I feel that Chernov has a point that we need to exert a certain amount of restraint so we don't become as bad as the enemy. 

The complex morals of the story is why World at War is one of my favorite shooters of all time. 

This went on way longer than I meant. What's your opinion?