Here is a possible explanation for the Occupy Wall Street protests which are currently happening around the world.
For a relationship to be satisfactory there has to be a more or less equal two-way exchange.
However, there is no law that says relationships have to be satisfactory, Furthermore, some people take advantage of others by exploiting or coercing them.
How do these observations apply in economics.
Throughout history there has been exploitation of some people by others. Mostly this has involved agriculture and force. The surplus has been taken. Mostly enough has been left for the producers to just subsist.
Starting with the Industrial Revolution three things changed.
First the surplus started increasing so that more could be left for the producers. Eventually during the recent years of prosperity the surplus was so large that many people (especially in the industrial countries) could have a nice share of it.
Second, population levels (at least in the industrial countries) have been low relative to the opportunities for employment. As wages are a function of supply and demand wages have been good and thus the surplus has been shared.
Third, those people who do the exploiting have discovered psychological ways of getting their hands on the riches of the world without using force. These include legislation which restricts competition, sneaky marketing, promoting the work ethic and emotional appeals such as to our greed.
To those of us who have been able to share the wealth it has not been clear that we have been exploited.
Once again, things are changing. There is some evidence we are now using resources at an unsustainable rate and there is now more competition for the surplus.
As the above listed psychological instruments are still working the rich are getting richer, the poor are getting poorer and the Occupy Wall Street protests are spreading around the world.