Hatred for the enemy

"I admit willingly that after the Normandy battles, my unit was composed of young fanatic soldiers. Many of them had lost their parents, or brothers and sisters in the bombardments. Some had seen for themselves at Cologne where thousands of bodies were crushed after the terrorist raids. Their hatred of the enemy was such that I admit that I could not always control them. At Malmédy, there were, no doubt, some excesses." - Joachim Peiper

Parker, Hitler's Warrior, chapter 18, citing La Libre Belgigue in note 61