I read a book that blew my mind. The main character goes crazy when he realizes no one really knows him.
The gist is that the person you think of as "yourself" exists only for you, and even you don't really know who that is.
Every person you meet, have a relationship with or make eye contact on the street with, creates a version of "you" in their heads. You're not the same person to your mom, your dad, your siblings, than you are to your coworkers, your neighbours or your friends. There are a thousand different versions of yourself out there, in people's minds. A "you" exists in each version, and yet your "you", "yourself", isn't really a "someone" at all.
From "Uno, Nessuno, Centomila" by Luigi Pirandello. (One, Nobody, One hundred thousand)