If people want to pay their government to help increase their happiness, once the basics are provided, it would make sense for the government to do so. This would be a volitional addition to what the Constitution says the government is to do.
Since one of the sources of unhappiness is a concern for security (and safety), it would make sense to set up arrangements that would facilitate that while avoiding setting up a system of entitlements. Security would be guaranteed for those who were responsible, but the guarantee would be provided by each individual be responsible within the opportunity that the system provides.
The pursuit of consumerism and spending is a source of unhappiness and instability. However, the economy is pretty much based on consumer spending. However, I propose that people would be happier allowing themselves a bigger personal safety margin and by reducing their expenses and space. They simply do not know how. A centralized project with private contractors would be able to set up to devise, implement, and market a system that could help in that process, probably for a slight, but reasonable fee.
WHAT HAS PROVEN TO WORK?
Although we would have to apply reasoning and some analysis before implementing, there are some usable ideas and principles that pop up from looking at what has worked.
The report concluded that economic factors related to health care, standards of living, and access to basic education were determining characteristics of a nation's overall attitude. Denmark, with its free universal health care, one of the highest per-capita GDPs in the world, and first-rate schools, came in first in happiness. (BusinessWeek.com. 10/11/06).