Inferiority complex, a psychological sense of inferiority that is wholly or partly unconscious. The term has been used by some psychiatrists and psychologists, particularly the followers of the early psychoanalyst Alfred Adler, who held that many neurotic symptoms could be traced to overcompensation for this feeling. The use of the word complex later gained acceptance to denote the group of emotionally toned ideas, partially or even wholly repressed, organized around and related to such feelings of inferiority. The term inferiority complex has lost much of its significance through imprecise popular misuse—for example, as an inappropriately facile explanation of any show of ambition by a person of less-than-average height.
Humans compete. In the course of competition, somebody has to lose. Losers
Frequently, losers develop an inferiority complex, but they are not free of competition, so they keep on losing.
But when you are in competition, you must act aggressive, competent, and self-promoting. That is, if you survive, you must develop a superiority complex: https://www.bustle.com/p/7-signs-someone-may-have-a-superiority-complex-17006240
Narcissists, of course, tend to have both inferiority complexes and superiority complexes. If those narcissists are talented, all of their factual claims might be true and correct, but people still hate them for being unpleasant.
Western society is competitive. It seems to generate narcissists at an alarming rate.