I think Chris Taylor said it perfectly in the last lines from the movie platoon.
"I think now, looking back, we did not fight the enemy, we fought ourselves, and the enemy was in us. The war is over for me now, but it will always be there, the rest of my days. As I'm sure Franz will be, fighting with Knorr for what Rhah calls "possession of my soul." There are times since, I've felt like a child, born of those two fathers. But be that as it may, those who did make it have an obligation to build again. To teach to others what we know, and to try with whats left of our lives to find a goodness and a meaning to this life."