Socialism gives human nature the benefit of the doubt

Compared to conservativism and liberalism, it seems as though socialists are the group most willing to give human nature the benefit of the doubt. At least from Heywood's interpretation and "spelling out" of what socialists believe it, this is a group that likes to think to best of society. While this optimism is all well and good and could both cause and perpetuate public service by making people feel like they are invested in each other's well-being, sometimes that optimism goes a little too far.

For example, at the end of Heywood's piece, he highlight's Marx's assumption that the state would eventually just wither away. Also, anarcho-communist Peter Kropotkin's assumption that people would work together in harmony within a stateless society reads a little like an episode of Barney. I do think there is something to be said for thinking the best of people and society, but too much of this positive thinking is more like wishful thinking.