At one time it was wrongly believed that ontogeny recapitulates phylogeny (i.e. the embryonic stages mirrors the development stages of the species). Similarly Freud thinks the phases that an individual goes through mirror the same phases that civilizations have gone through. Freud uses that theme to explain his psychoanalysis in describing individuals and the societies in which they live as mirror images of each other.
Yes, Freud does believe some weird things and he restates them in this book such as the early infant's whole world is the mother's breast and thus we end up fetishizing the breast when we grow up, our time in the womb means we always are looking to return to an abode of some kind, something about the anal fixation and how it never leaves us and unrepressed sex desires lead to our anxieties and other such things that sound weird to our modern ears. But those distractions don't necessarily mean that this book is not highly engaging and worth reading. I'll challenge you to read any recent biography because you''ll almost always see the author slip into Freudian speak (e.g. I'm currently listening to "The Purple Diaries: Mary Astor", and the author says that her father was strict and controlling and that made Mary Astor not trusting of men and unwilling to share her feelings with others particularly men, a very Freudian interruption). It's not a bad way of seeing the world. It's how we understand our selves or others. Now days, we just don't add on the word neurosis or repression, but it's how we cope with the nature within ourselves and others.
I like this book for the same reason I liked Nietzsche's "The Genealogy of Morals". I don't agree with what they are saying, but they provide a narrative that is compelling. Matter of fact, you can tell that Freud is really influenced by Nietzsche within this book. Freud will say something such as the "conscience of the individual gets repudiated by the instinct leading to an anxiety that gives a person guilt" and that leads them to the wanting of taking away of the power of the father. (I don't have the quote exactly, but I think its fairly close to what he was getting at). Nietzsche's "will to power" at it's most basic cries out for how the community takes away our primal instincts, takes us away from "mans instinct to freedom". What Freud does within this book is argues Nietzsche's viewpoint with the emphasis slightly different. Freud states that our conscience gets perturb from within the family and by extension within the community leading away from our authentic (not a Freud word, but I feel comfortable using it here) selves.
As I was listening to this I had to pause to see what year he wrote this book. I noticed it came before Heidegger's "Being in Time". Heidegger had a long section on 'conscience', and seemed to conclude that the conscience is the cause of itself. Freud does a similar thing (if you take his complete statement on the topic within the book and you relate it to the father of the individual as he does or as he does latter on in the book to the sacrifice of the Messiah on the cross, he makes it a complete circle thus giving itself as its own ground (I think)). "Will" is defined as it's own cause by St. Thomas Aquinas thus giving our conscience its primal place in his theology and leading to free will such that God can judge us for our moral acts in a necessary universe but which was contingently created by God exercising His will. Freud is giving us our conscience as a thing in itself and thus we can be blamed for who we are or became (even if we are schizophrenic, autistic, or predisposed to alcoholism by genetics, or whatever).
The conscience leads to guilt because of our repressed neurosis (he'll say). Nietzsche will say the guilt is not real, Heidegger says it is because of the debt we owe to the future because of the one absolute truth we always know (our own impending death), and Freud says we have the guilt always but we repress it thus leading to our neurosis. (I love using that word 'neurosis'. It's totally void of meaning and I think the DSM V doesn't use it at all as a category for that reason). All three are trying to return to us our authenticity which has been taken away from us by civilization (and the family).
Freud in this book also lays out a defense for the importance of character, community, and science and aesthetics in the development of the individual and the functioning of civilization as a whole. He dismisses religion. The neurosis (there's that word again) that exist in the individual also exist within the civilization as a whole (he'll say). By character he is getting at blaming the victim. It's the values that the individual (and species) are not learning properly from their community and will later on allow for 'refrigerator mom's' to be blamed when their child is schizophrenic or have autism. He'll even say that civilization as a whole is currently (1920) suffering from neurosis.
Freud lays all of this stuff out in this book. Do I agree with any of it? Not at all. But, there is a narrative that Freud uses that is fun to follow. I liked this short book so much, I'll probably buy "The General Introduction to Psychoanalysis" by Freud that audible offers which I would guess will cover most of this stuff in deeper detail.