Everything in the world may be endured except continual prosperity. – Goethe

So long as all the increased wealth which modern progress brings goes but to build up great fortunes, to increase luxury and make sharper the contrast between the House of Have and the House of Want, progress is not real and cannot be permanent. – Henry George, Progress and Poverty, 1879

Human prosperity never rests but always craves more, till blown up with pride it totters and falls. From the opulent mansions pointed at by all passers-by none warns it away, none cries, “Let no more riches enter!” – Aeschylus

Luxury… corrupts at once rich and poor, the rich by possession and the poor by covetousness. – Rousseau, The Social Contract, 1762