The theaters of Ancient Rome were so spacious it was difficult for spectators to see the actors' facial expressions or hear their words. To accommodate those in the farthest reaches, actors used masks with megaphone-like mouthpieces called personae from per, "through" and sonare, "sound." The actors eventually became so closely identified with the masks, that they would later be collectively designated "the dramatis personae," "the members of the cast."
Over the years, the word "persona" mutated from a character in a play into a person, a general word for a human being, This led many to confuse who they are as a person with who they were pretending to be — their persona.
Who is that masked man? That's a tough question. When you regularly wear a mask, it becomes increasingly difficult for people to remember the person behind it. It's an especially acute problem for actors and politicians who often carry their stage persona into real life. It's incumbent on them as well as each of us to differentiate the roles we play from our essential being.
Shedding that mask and acknowledging the person who is beneath is an intimate and personal matter — individual and private, between you and your real self.
There's nothing personal, however about personnel. It was the noted Social critic, Paul Goodman, who raised the question, "People or Personnel." Personnel first entered the language to delineate between people and material resources available to an organization. With consolidation, they became "a body of people engaged in service or employment in a public institution," housed in — what else? — personnel offices (c.1960), departments which oversaw hiring and firing practices, which, unfortunately, were anything but personal.
Confronted with their fundamentally impersonal nature, they transformed themselves (by name only), hiding their activities behind the more acceptable rubric, "Human Resources," hoping thereby to disguise their true personality.
Personality once referred to one's personhood or humanity. Through the years, however, it moved from the general to the individual. By the 18th century it spoke to a personal identity, and soon we were speaking of people with a weak or strong personality, one that is either dominant or subordinate. "She's got a great personality" men especially like to say of a woman in possession of less than outstanding physical attributes.
The word has now moved on to celebrity status. It speaks to renown — being a real personality, i.e. a distinguishing set of characteristics, those aspects of yourself you choose to show to others, preferably on TV, over the Internet, on Twitter, or in a tabloid — which brings us full circle back to the mask you wear when dealing with the world.
Only when people remove that mask can we distinguish their personality from their character. Being a personality can make you a real character. Having a great personality, however, does not always make you a person of character. For that you may have to go to the Yiddish word, "mensch" — a real human being, honorable, one worthy of emulation, and worthy of the designation — if we may say so personally.