Things that teach “what it is to be a human being” also teach us useful things about constructing software (or any other tool/affordance, especially when building in collaboration with others): history, philosophy, anthropology, ethnomethodology, &c. Note that some lessons in this category are best transmitted by literature, theatre, poetry.
A parallel: in medical literature one eventually notices that almost every ailment or complaint is improved by making the organism more healthy (diet, exercise, sleep, &c). In the same sense, everything one does to become a more compete person improves outcomes over a wide field of potential activities.