"Human beings must either give or fight." (The Gift of Thanks, Margaret Visser, 2008; page 110)
When a society encourages covetousnous people come to desire what others have, and inevitably they start fighting over who gets to own it.
In societies where people tend to diminish the power of material goods, harmony tends to rule.
We learn to covet what we see others enjoying. That's what so much of advertising is about.