Indeed, it started out with just survival, and the survivors have mastered that for the most part by now. But it follows that when society breaks down, the niceties that bind us to certain conduct expected of a functional group will go with it until order is established. One could go so far as to equate Hannibal, the conquerer who managed to sack Rome, with antagonist negan possessing many similar characteristics. Hannibal kept his soldiers on the March for a twenty year campaign, and was a tactical genius. He was respected, loved, and feared by his troops. He was also increadibly cruel when it came to punishing bad conduct among his own men, and it's one of the things he is still remembered for.
What happens when the rules of conduct are peeled away from the elements of society who, underneath, are already cruel and heartless? Those who, within our society, function as expected because it is expected, but without any rules, rise to the top as the heartless conquerers?
Before great nations, humans have always been petty and cruel to each other. Tribes would often wipe out other tribes, killing all the men who couldn't be made slaves and taking the women for wives.
Natural human behavior is full of drama.
Wow such an intelligent answer! Nd very English professor y aha I loved it though