insufficiency
For the following to make sense, let's define 'evil' as not something that is completely unjustifiable, but an act whose drawbacks far outweight its benefits.
Whatever arguments exist in the world today, they can all be traced back to insufficiency. The first argument between two humans probably caused by something like a lack of food. Two humans were starving. They saw food, but there wasn't enough for the both of them. So they argued over it. Substitute whatever resource you will.
Almost all arguments in the world today are caused by a dearth of something. Take the controversial issue of Israel/Palestine, for example. What's a major part of the problem? Land. There is not enough land. Another example, why are there so many arguments about energy these days? A lack of fossil fuels.
Eventually, people are going to get greedy and hoard all of the resource of which there is a dearth, assuming that there will not be enough to go around. Maybe there is enough for everybody, but those who are greedy will take nonetheless. So, to a certain extent, I agree with bpat1434.
Why can't we all just get along? (Kum-Bah-Yah time everybody! 😃)