At the end of the day I truly believe in Socialism and how it can work if people are honest and empathetic. On the other hand I recognize that if even one person f*cks up in socialism by virtue of lacking honesty, integrity and empathy, then the whole system crumbles. And this is easy to achieve considering we recognize the existence of sociopaths. Sociopaths will tend to be high achievers who lack empathy. Socialism is the current most corruptible form of government in the world, where one person being corrupt could have major implications down the chain. Communism would remove the chain entirely however it is unachievable outside the realm of fantasy. Communism was never attempted in real world because: 1) We has societies have no way of actually implementing it without completely tearing down existing systems of power, and then the powers that helped us achieve that ad infinitum. 2) Even if we did form a communist society from scratch, the concept of human nature and our inherit competitiveness as a species would impede the formation of such systems. It takes one person against the system to absolutely make it not work, and it would usually be the most productive/ accomplished members that feel the others aren't contributing to society appropriately that are against communism. Those individuals highly value meritocracy which communism inherently devalues.
