Real socialism as present in the Soviet Union, East Germany etc. until 1990 was characterized by the total absense of markets. The government planned and ran the economy, tried to figure out needs, shortages, fixed prices (if prices were used at all), gave out production targets to state-run factories, and everything failed as there were no incentives to produce efficiently, no market prices that gave incentives and regulated the balance of supply and demand.
I wonder what country still has a system like that. What some seem to define as "socialist" in this discussion, is actually what has been coined "social market economy" in Germany, a market economy in which the state interacts when there are market deficiencies and in which some areas such as healthcare are not left to the free market without some control.
But social market economy is far from being socialist in the sense that incentives to work efficiently are eliminated. I don't think general health insurance makes people lazy...

Edit: Found a good link about social market economy:
https://www.dw.com/en/can-germanys-socia...ears/a-50490937