Some observations from two foreigners (a US engineer and a British diplomat) working in Afghanistan about the work ethics of the Hazaras:
When the men from the south were gone I called for volunteers among the Hazaras, feeling intuitively that at least we had come among men again instead of children… In the first place, even from two days’ acquaintance with the steady Hazara people, I felt free to leave the pack train in their charge without remaining constantly in sight.
Fox, E. F. (1943). Travels in Afghanistan, 1937-1938. New York: Macmillan. p. 251-252
The Hazaras differ radically from the Afghans, with whom they have been constantly at feud, and retain many of the traits of their Central Asian ancestors. They are honest, courageous, good-natured, and simple. They make excellent servants, first-rate solders, and cheerful labourers.
Fraser-Tytler, W. K. (1950). Afghanistan: A study of political developments in Central Asia. London: Oxford University Press. p. 57
About non-Hazaras, I have posted some interesting quotes too, click here.