He's always been different, ever since childhood. An awkward boy wearing superhero t-shirts, sitting inside during recess to review papers on electron arrangements, a college student by eleven and a PhD by sixteen. The mockery from inferior minds has bothered him, of course- dealing with the sheer idiocy that characterizes much of humanity is a cross he must bear- but he's never thought their reactions to be his fault. Sheldon Lee Cooper, homo novus, is simply too advanced for the plebeians to understand. His hobbies, his word choice, his intellect, will not be sacrificed on the altar of social convention.
So he shouldn't take it personally when a driver decides to splatter the nerd he saw on the side of the road with sticky flavored ice, or when restauranteurs goggle at his android get-up. He's been treated to worse assaults from neighborhood boys, been greeted by much more piercing stares. Only for the first time in his life, he isn't an elusive outsider, high above the madding crowd. He feels like an idiot, a grown man dressed in costume clothes, trying to report a car theft to an officer who thinks his mother needs to pick him up. Nobody here knows that he's a renowned physicist at Caltech- they just see him as an overgrown child. He absorbs their disdain and quails beneath it.
When he was ten, he used to fantasize about Spock sweeping him away to Starfleet Academy, to a place where he would be valued for his prodigious talents, his offbeat interests. Humility, at thirty, tastes bitter in his mouth.