Quote from : The World as Will and Representation, Vol 1 Book

All striving comes from lack, from a dissatisfaction with one's condition, and is thus suffering as long as it is not satisfied; but no satisfaction is lasting; instead, it is only the beginning of a new striving. We see striving everywhere inhibited in many ways, struggling everywhere; and thus always suffering; there is no final goal of striving, and therefore no bounds or end to suffering.