Sigmund Freud had uncanny insight into our psychology

How Freudian Theory Gave a Start to the Manipulation of the Masses

Sigmund Freud had uncanny insight into our psychology | that is, the things that went on inside our mind. His theories may not have been so palatable to some people, such as the Oedipus Complex. But it was his notions of unconscious impulses and defense mechanisms, which have been his lasting contributions to Western culture, language and ideology. So while some may dismiss these ideas, or even despise him personally, there's little denying his pervasive influence throughout the 20th century. It is really no surprise, then, that his daughter (Anna Freud) and nephew (Edward Bernays) drew on his thinking. Many, many others did, too.

More pointedly, Freudian theory underpinned what must've been quite a lucrative consultancy for the aforementioned nephew, that is, for major companies, organizations and governments with whatever "products" to push.  In my framework and language, crack The Human Algorithm, and you have every opportunity to sway the masses.