How about this idea?
The entire economy is actually a service economy. If you think about it, nearly everyone works to serve others. People grow grain so others can eat, produce cars so others can drive, build so others can live, make movies so others are entertained, teach so others better serve other people. Consultants, therapists, coaches, and volunteers are only more explicit in their servitude.
So we dedicate our lives to help others along. As parents we breed children, as children we take care of parents, and if we do not have anyone to care for we say we are working for the sake of the generations to follow, so we continue helping others along.
If you look at human activity this way, the assertion that humans are selfish is silly. You also are inclined to conclude that all the work we do is simply occupational therapy: we keep each other busy to keep the circular flow going. What is the end of it all? What is the purpose? Society is like a club that is set up to serve its own sustenance.
What is wrong with this way of looking at the economy?
Which texts can we bring in to alter this picture?