Silence.
It wasn't cold or awkward, though it wasn't really friendly, either. It wasn't angry, but it also wasn't the kind of comfortable silence that followed reconciliation. Still, for some reason he didn't quite understand, it was so much nicer than the noise. It was a very gentle silence, soft and peaceful, laced with just a little bit of comfort. It was just enough to get him from one day to the next.
He couldn't remember exactly when he had begun to differentiate between the different kinds of silence, but he knew how to identify each and every one of them instantly. It was almost as if he had honed a sixth sense for the specific purpose of defining a situation based on its nothingness. Because he was so very, very familiar with nothingness, and it was the classification of that nothingness that kept him sane.
For example, when he tried to talk to people and they ignored him, passing right through his body as if he weren't there. He hated that silence. It was the non-believing silence. It was a silence so completely indifferent and apathetic that it was almost spiteful. It was the 'you're not really there' silence, and of all the silences his three hundred years had shown him, he hated that one the most.
Then there was the disapproving silence, like the one he received from a certain guardian after the Blizzard of '68. Or the one he got from the yetis at the North Pole when he tried to sneak in. The 'you're always going to be a nuisance, aren't you?' silence. Or the 'I can't believe you messed up again' silence. He hated those, too, though he didn't hate them half as much as the first.
But then, sometimes, if he was lucky, he got to experience the peaceful silence. That was the silence he loved, the one that fell on his ears as he sat in the snow beneath a star-spangled sky, tangled in the web of his own thoughts. It was the kind of silence that made him feel like he was real—like he existed. It was the kind of silence that let him close his eyes and pretend for a moment that he was staying out past his curfew and would return home later that evening to be scolded by his worried, loving parents.
He remembered the one time he had tried to talk during the peaceful silence. There was no response, of course, and it had shattered everything he worked so hard to build, reminding him exactly who he was: Jack Frost, the spirit no one believed in. Jack Frost, the spirit no one saw. Jack Frost, the spirit that didn't matter. After that, he never tried to speak during the silence again. Ever.
Instead, he sat there, on the ground, in the middle of the wood, just as quiet as death and twice as cold. He would pull his knees up to his chest and wrap his arms around them, his staff clenched his in his fist, his hood pulled up over his head. His toes would curl through the freshly fallen snow, courtesy of himself, and he would listen.
He would listen, and then, after a while, he would begin to drift. His mind would slowly fade into blackness as every harsh reality about the world he lived in faded away. Glassy blue eyes would drift shut, and then his body would slump against the nearest tree or rock, the last bits of consciousness fading from his thoughts as he allowed himself to tumble into darkness.
Silence.