We disagree about value.
Our combined wealth increases by the amount of the disagreement. This is miraculous, because there's only a rearrangement.
There's a story of a chaplin in a WW2 prison camp who would take his monthly Red Cross box and set out trading cigarettes, meat, jelly, and so forth, each trade reflecting the preferences of the other guy, say of jelly over cigarettes, and return to his bed with the equivalent of two Red Cross boxes. All he did was know who preferred what, and came away leaving everybody better off, yet with a profit also to himself. This is the vocation of the middleman. Disagreement is his melieu.
All voluntary trades raise the combined wealth. Trades that don't benefit both sides don't happen, at least not voluntarily.
Add up the voluntary trades over the nation, and the national standard of living rises by that amount.
The rule for generating the maximum amount of disagreement over value is: specialize and trade. The specialist values his output at much less than his customers do, and so he acquires a job. So long as the disagreements survive, his job is economically possible. The national economy booms.
For his needs, the specializer trades with other specializers.
Self-sufficiency, by contrast, is the route to extreme poverty.
Obama is the master of closing disagreement gaps, and with each closed gap a job disappears. Obama's is the economic policy disaster of the century.