Post Carbon Fellow Chuck Collins was interviewed on how wealth divides us in Sun Magazine.
From the interview:

Wildhood: Why should we be concerned about inequality? How does it hurt me for someone else to make a hundred or even a thousand times as much money as I do?

Collins: Extreme inequality of wealth, income, and opportunity is warping everything we care about. It takes away the sense that we’re all in the same boat. It screws up communities. You can see it in the housing market, where wealthy buyers bid up prices, making homes unaffordable for everyone else. It creates economic volatility even for the rich, which is one reason why the wealthy cling to their wealth. We live in a society where even people who don’t appear to be at risk can lose it all, and the fear of that happening makes them greedy and shortsighted.