Real jobs. Take a manufacturer for example. They make valuable product. Proceeds from product sales pay the work force, buy raw materials and parts, pay the bills, and buy production machinery. If the product is a good one, sales increase, the factory expands, more people are hired. The money that sales brings in, goes right out again, increasing demand for food, clothing, housing, raw materials and so on.
Govt jobs. Take a bureaucrat for example. They don't produce anything valuable. There are no proceeds from sales. The bureaucrat's pay is money taken away from the citizens by way of taxes. The citizen's could have spent that money just as well as the bureaucrat does. The more bureaucrats the government hires, the more money it takes from working citizens. Government workers are a drag on the economy, they consume but they don't produce.
And yet, lefties will tell you that government hiring is required to "get the economy going". I heard that a couple of times over Christmas.