I knew this guy once, named Joe. Raconteur, man about town, serial philanderer, the kind of smooth talker who could gamble away his entire paycheck in one evening of playing craps with his buddies in the back room of John's Bar and then somehow manage to talk his constantly-pregnant young wife out of being furious at him. When he got very, very drunk you got the sense that there was a big hole there where the "person" was supposed to be; you had the eerie sense that you were dealing with some cleverly-designed construct that merely emulated a human being. Joe's "Rosebud" moment happened when he was 8 years old. His beloved father, a young man of 28, died slowly of blood poisoning from an abscessed tooth (this was the pre-antibiotics era, and poor immigrants generally couldn't afford proper dental care). The last words he heard from his father (delirious from infection and mostly likely insane from pain and fear of death) were words his father screamed at him: "Who are you? WHO ARE YOU???" I believe Joe grew up and spent the rest of his life trying desperately not to answer that question. At the age of 77, he made the calm, rational decision to starve himself to death as penance for his sins, real and perceived.
He was my Dad.