I love this question.
The answer, of course, which many of you may know, is Pierre Gringoire, one of the main characters of
Notre-Dame de Paris by Victor Hugo.
No one will probably read all of this, so I will summarize.
Pierre has found himself accidentally married to a beautiful gypsy woman, having already previously that same evening been evicted from his home, refused payment for his play, fallen asleep under a mattress in a gutter which was subsequently set on fire, entranced by a goat and a song, captured and kidnapped by thieves, forced to attempt feats of agility which ended in him face-down on the floor on top of a mannequin covered head to toe in hundreds of little bells, staring face-to-face with DEATH ITSELF more than once, AND ON TOP OF THAT, HIS HAT WAS TAKEN AWAY. Oh, the pity of that. It was such a good hat.
SO! At last, alone in the room of his gypsy wife, he attempts to sweet-talk the young lady, which first confuses her, then obligates her to draw a knife on him, at which point he IMMEDIATELY gives up on THAT, thank you very much. He'd really rather just have a snack. But he doesn't drop it entirely. He must know why. And what. And quote things in many languages as he does. He is incredibly annoying.
Esme: "Why were you stalking me?"
Pierre: "I don't know. Why do you have a goat and why is your name what it is and why is the sky blue and why do you sing in that language and--"
Esme: "I don't know."
Pierre: "Yes, but WHY??"
Esme: ...*vague explanation involving a shoe*
Pierre: "What is that? Where did it come from? What do those words mean? What language are they? Where do you come from? Are you an orphan? When did you get here?
Are you psychic?? Who was that guy that likes to break stuff? What--"
Esme: *OMG STFU* What is your name, anyway? I suppose I might as well know, since we're married and all...
Pierre: *MOUNTAINOUS TEAL DEER ON STEROIDS* *RELATES ENTIRE LIFE HISTORY, EVOLVING INTO A CONVICTED IDEALISTIC MONOLOGUE DESCRIBING A BLISSFUL FUTURE AND ENDING IN A POIGNANT POETIC ENTREATY TO SENTIMENTS OF CHASTE BONDING*
Esme: Cool story, bro. *totally unrelated lingual query*
Pierre: ...*answers with shocking brevity*
Esme: OK. *DISAFUCKINGPPEARS*
Pierre: ...*blink* *shrug* *calmly drapes himself over a wooden box or something and goes to sleep*
You see, other than the being kidnapped by gypsies and married part, this has all happened to me... pretty much verbatim, in a lot of places. This and much weirder shit. Pierre is somehow perfectly the essence of so much of who I am. This includes randomly, outtafuckennowhere, deciding to stalk total strangers in the middle of the night, sleeping in BIZARRE locations, waxing poetic at GREAT length, taking every opportunity to slip in intellectual shit, and having absolutely no real interest in sex.
Throughout the entire book, every scene Pierre is in is something essential to who I am, some situation I'd handle exactly the same way, some gesture I'd make or conclusion I'd draw, the same reactions, the same motivations (or lack thereof)... It's like Victor Hugo peeked forward in time and wrote me into a book.
I will say, though, I feel like I'm not ALWAYS as big a flake as Pierre can be, and when I'm not Pierre, I'm Ratty from
The Wind in the Willows. Indeed, he was the character I most identified with from about age 5 to until I read
Notre Dame for the first time in my senior year of high school.
The third character who is essentially, completely, all-emcompassingly me is Judah Low in
Iron Council by China Mieville... but that version of me is not written quite as humorously and self-mockingly as Pierre, and Judah is the me I prefer not to advertise because I know people will completely misunderstand it. If you REALLY want to know, you'll have to read the book, because I'm not explaining. I know better than to confess to crimes you haven't committed but WOULD without so much as a second thought or a moment of regret.
EDIT: And of course, Spock.That's just a given.