The British retreat to Corunna under Moore was undisciplined and the British troops pillaged and looted their way through the villages there.
And the enforced evacuation of the Portuguese population to the area behind the Lines of Torres Vedras ended up causing between 40-50,000 dead Portuguese civilians from exposure and starvation. John Grehan's excellent book on the Lines covers this aspect which is usually ignored.
And the Spanish guerillas also made war on their own people, some of the guerilla bands being nothing more than sanctioned bandits. Spanish civilians were abused, kidnapped, etc., by the guerillas on a regular basis.