There are a shitload of jobs that are (as coronavirus crisis and the list of jobs deemed essential in many countries shows) "much needed" for keeping a country running: anything medical, public transport, childcare/education, logistics, groceries/other food, infrastructure upkeep (electric/water/phone/internet/gas grid).

But unlike jobs that label themselves "system critical" such as banks, investment vulture funds and others of their ilk, the really essential jobs have one thing in common: extremely shitty pay, sometimes outright exploitative working conditions.