"This aspect too of 'intellectual work'—the exaggerated value which is put upon the 'difficult' simply because it is difficult—becomes evident in the accentuation of a particular trait in the look of the 'worker': the fixed, mask-like readiness to suffer in vacuo, without relation to anything. It is the absence of any connection with reality or real values that is distinctive. And it is because this readiness to suffer (which has been called the heart of discipline, of whatever kind) never asks the question 'to what end' that it is utterly different from the Christian conception of sacrifice. The Christian conception of sacrifice is not concerned with the suffering involved qua suffering, it is not primarily concerned with the toil and the worry and with the difficulty, but with salvation, with the fullness of being, and thus ultimately with the fullness of happiness: 'The end and the norm of discipline is happiness.'"
Josef Pieper, Leisure: the basis of culture, trans. Alexander Dru (San Francisco: Ignatius Press, 2009 [1963/1952]), 35. The closing sentence is from Summa theologiæ II-II.141.6.ad 1 (not 5.ad 1): temperantiae ipsius finis et regula est beatitudo.