Work is one of the major sources of purpose people have. Earning an income and putting food on the table is fundamental to one's self-respect. Like educational achievement, it gives the impression that there is some way to advance beyond your lot. Take that away and it will cause a mass existential crisis unless there is something to fill the void. All the blights of the rust belt and other economically overlooked areas should be expected to spread.
Eh, that's a wild assumption. If anything, automating away crap labour that barely keeps you sheltered and giving people the economic stability to focus on something long term should enable various forms of self-advancement for masses of people who are now just stuck doing a crap job until they get to retire.
Such as?