They fear what they cannot understand. She reminded herself of this daily, when kids stole her shoes, or stared openly in the hallways, or neglected to lower their voices when gossiping about "Looney". They cannot understand what they will never see, and they fear that which they cannot understand.
Because they could not see the universal patterns of magic embroidered into Hogwarts' very air, because they could not hear the tiny creatures that sang to her in the afternoon sunbeams, because they could never feel the emotions of strangers rising and falling like tides against her shoreline skin- they could never understand her plane of existence, and so she was apart from them.
It sometimes seemed overwhelmingly odd; it was common knowledge that muggles could not perceive the many wonders of the wizarding world. It was not considered unusual for a wizard to hide among the muggles, coming off as Looney because they knew so much more. Her peers, her teachers, and her friends all knew this. But they couldn't make the jump. They could not step far enough out of their own little lives to think that maybe there were truths that wizards couldn't grasp. The mind is vain, she supposed. It never wants to admit there could be something beyond its reach.
And so days went by, long and lonely, in which she did her best to be subtle. It was difficult to remember, but those who fear you are quick to turn on you, so she was mild. Quirky, maybe. She held her books upside-down to read them –it's just as easy, once you get the hang of it- and only mentioned the most mundane of the things she saw. There were joys of fulfillment, in her studies, in the wonders she observed, and even in the common social interaction she enjoyed with the witches and wizards.
But it's always been lonely at the top, for animals, for muggles, for wizards and for anything beyond that. Which is why, that day when she received a note, everything changed. She had been in the library (not studying- watching the Gurzlewarves collect dust motes from shelves. She felt they would begin constructing their nests soon). And, suddenly, there was a note on her table. She didn't see it arrive, but perhaps she had simply been distracted.
There was nothing distinctive about the handwriting, no signature on the page. Just five little words, stark against the page: I see it all too. And then the world didn't feel quite so lonely.