I just finished reading "We were soldiers once, and young". It is the story of an early battle in Vietnam, and part of the battle was an ambush of our guys where they were just cut to pieces. As night fell and our guys finally had formed something of a perimeter, they could hear the NV soldiers walking through the tall grass, finding our wounded and shooting them, all the while talking and laughing. And they wouldn't just shoot them in the head and finish them off - they would put the gun in the GI's mouth and pull the trigger.
It's not like I didn't know that happened, but reading about it was still disturbing, and it made me proud to be an American, because, I thought, that's the difference between us and them.
Until I read these threads where freepers cheer because some Marine executed a POW.