Okay, so I DM for my girlfriend's family. They're all pretty low level, broke, and try to be good people.
I had them fight through a camp of kobold, and upon reaching the "boss room," they get dropped down into a pit where they have to fight in an arena, gladiator style. The boss ended up being a homunculus, but some of the lower-level enemies were villagers from the local town.
The party had to kill the villagers, because there were close to 100 kobold with bows that would rain down hell on them if they didn't. There were villagers in the waiting stable as well, mostly women and children (kobold aren't big, so men are a hard target).
Anyways, they start killig villagers and they're just broken up about it, so the homunculus starts tossing bags of gold down for every slain enemy. My party's greed got the best of them, and they continued to slaughter innocent people for money and the enjoyment of the homunculus.
After finally wading through the blood of townsfolk and beating the homunculus, the homunculus leaves, but the party heard an explosion. The way out of the arena was through a hole in the stable, which was underground. It went up. The falling rubble killed all the townfolk they had initially wanted to save.
They don't want me to make my own quests anymore.