It's an old story, often told. Some dark-haired, greasy, brilliant kid with a notoriously bad-boy reputation falls for an innocent, untouchable girl he lauds as some kind of angel. He was obsessed, she was naive, and no matter how you spin it things like that seldom end any way but badly.
He kissed her a couple of times. She laughed it off; pushed his hands off her shoulders even as she was kissing him back, turned away before he could see her weak knees, her desire. She would never tell him she shrugged him off because she couldn't breathe every time he walked past. She was terrified of the implications; possibilities she forced herself to close her mind against. She resigned herself early on to the fact that they could never have an actual future, not with his unhealthy habits; his questionable friends.
Even if at one point she was stupid enough to fancy herself a bit in love with him she let his occasional scorn and his passionate advances eventually drive them apart. He could be cruel when he didn't get his way. Later on she realized she had broken his heart but at the time she hadn't thought he'd consider the cessation of their troubled friendship that much of a loss.
Oh, it's not as if they never talked again - life is seldom that dramatic - but they fell further and further out of touch until one day it was too late to fix things; too late to fall into the comfort of stolen kisses, of classroom camaraderie.
She moved on, grew up, stopped thinking about him except in passing. She fell for another dark-eyed, messy-haired boy and lived an entirely different life than the one she had allowed herself to entertain the occasional fleeting fantasy of so many years before.
She wondered, though, for a long time, if had she been a little less naive, a little kinder, a little more patient, she could have somehow saved her wild boy.