Mary Sue: “A variety of story, first identified in the fan fiction community, but quickly recognized as occurring elsewhere, in which normal story values are grossly subordinated to inadequately transformed personal wish-fulfillment fantasies….”
Guilty as charged. As far back as grade school, I remember building mental images of myself as Superman, bringing fictional characters from all genres to Disneyworld in an elaborate imaginary crossover. I even kept souvenir guides from Magic Kingdom and EPCOT Center, and I would pore over them, planning those fantasized trips for hours and hours.
And oh, those high school days, when I would type up (I used a typewriter back then) nascent Star Trek novels (Classic and Next Generation), always starring a big, strong, silent, intelligent, furry, felinoid anthopomorphic lion-hero who could scuba dive, had psychic powers, and would eventually hook up with a beautiful feral furry felinoid partner from his home planet. (Broke the pattern just once to write up one about an anthropomorphic mutant rat on Captain Picard’s crew.) And those endless role-playing game campaigns, where I would always play the mysterious warrior-wizard with a lion familiar, or the mysterious Veritech-piloting scientist and time traveller from the future. (I was really attached to that lion familiar, too. I remember overturning a chair in anger when it was killed by an evil-aligned teammate. You know who you are, Fry. I will avenge that lion yet. ;)
Related: “Quantum Kirk.” And has it ever occurred to anyone that one reason some Apocryphal Gospels didn’t make it into the Canon was because they read like bad Mary Sue fiction? Seriously, Thomas’ noncanonical Boy Jesus Account — transforming clay into sparrows and killing the annoying neighbor kid with a word — sounds a lot like how a fanfic would read if early Gnostic teenagers were the ones writing Harry-Potter-like fiction on clay tablets.