The basic outline of Freud's thought is well known. Freud believes that our visible rational world is a kind of veneer over what really makes us what we are, which is a battlefield of conflicting desires that are in our subconscious. We tell ourselves that we are acting based on reasons, when in fact we act based on the dictates of our desires, and the restraint imposed by the internalization of social rules. The tension between desires and rules is almost unbearable, but we keep it together with our rational account of things. However, that conflict finds its own ways of becoming manifest, and does so regularly, in dreams, jokes, symptoms, slips of the tongue (parapraxes), and a variety of other ways.
Freud thought that this account not only described the individual, but also the society. Critical theorists agree with that observation (although perhaps not with the way Freud worked it out). Our societies are comprised of desire, with a sheen of rationality overtop. And, we have not learned well how to deal with the conflicts underneath. We allow all sorts of inequities, and convince ourselves that there is no other way, or that these things are somehow inevitable. We convince ourselves that we can fully understand and control our actions.
For more on Freud, go here.