Whether you are happy with your income depends on how it compares with some norm. And that norm depends on two things: what other people get, and what you yourself are used to getting. In the first case your feelings are governed by social comparison, and in the second by habituation.
Because these two forces are so strong in human nature, it is quite difficult for economic growth to improve our happiness. For as actual incomes rise, the norm by which income is judged rises in step.
(Was man von Wirtschaftswachstum erwarten kann, wozu es tatsächlich gut ist und wie Wirtschaften nachhaltig möglich ist, lasse ich jetzt einmal stehen)
Bild “Euro”: © Thomas Siepmann / PIXELIO