I confess the one I just added was somewhat grim but... well, marauding and pillaging tends to become the norm when the land you live on cannot provide what you need to live comfortably... and cannibalism tends to become more normal when stable food supplies aren't happening with a large group of people.
The two tend to go hand in hand a bit, since it's a lot easier to kill and eat someone if the only thing you know about them is that they stabbed Frank in the gut.