Humans are neither good nor bad. On a day to day basis they are apathetic at best and self centered at worst. Given thousands of years of social and moral progress we've managed to work out efficient means of living as social species and thankfully we do have things like empathy, sympathy and compassion. Unfortunately these are easily suppressed and the average person will effectively meet out genocide given the right circumstances (see Mao's great leap forward, Stalin's Purges and Hitler's Holocaust).
If you want to understand the "Jungian Thing" (the duality of man) you need to understand where we came from. Our sociobiology. This notion of the nature of humans is perhaps the greatest presumptuous fallacy of human history. We are just machines responding to the environment around us. The notion that we are "good" or "evil" is an illusion. We can only judge actions based on our subjective goals while ignoring what it means to live in a deterministic world. We think we are autonomous creatures that make moral decisions based on reason. There is little evidence to support such a position.
This is not to say that reason and logic do not influence our decision making process. They do. Just not in the way our egos would like to think.
For source material I would recommend Hanna Arendt's Eichmann in Israel, EO Wilson's The Meaning of Human Existence and On Human Nature. I can also recommend studies and other academic source material if you are interested. There is a wealth of science as to the nature of mankind and it's not as cheery as you might imagine. Which should be obvious given thousands of years of wars, oppression, slavery, genocide and unimaginable atrocity.
I would not say we are "well intentioned", that again is an illusion. We are self interested. However, it is in our rational self interest to be kind, charitable and well intentioned. It's also in our rational self interest to be back stabbing, deceitful bastards. There is no single strategy to Maslov's self fulfilment. Donald Trump made millions and perhaps billions making people homeless. Is that a good thing or bad thing? FDR committed crimes against humanity. Lincoln suspended Habeas Corpus. Reagan traded arms for hostages. The list goes on and on. We can be a kind and generous species and then, given a little fear (see 9/11) we are willing to give away our plain and precious freedoms because we are little more than children huddling in the dark pretending to be brave. It's a lie.
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