The hell that high school was for him was mostly his fault... but he didn't think so then.
Weaving through halls as if traversing enemy territory, scouting every room and corridor for possible threats, assuming bad intentions lurked behind every set of eyes: this is how he approached each day. Everyone has ulterior motives. Trust nobody. Never turn your back. These were his mottos.
In his mind, every laugh was at him; every whisper about him; every gesture toward him. Each day became a countdown to exactly 2:37pm, dismissal time, and then walking home was an elaborate affair, a way to get to safety without encountering predators. Paranoia reigned supreme.
It's true that some of the taunts were real. Most days would involve an encounter with at least one bully -- the only truly mean-spirited ones out there, the ones who picked on the unpopular to boost their own popularity. He was in a Catch-22 here; ignoring them only led to worse baiting, and fighting back led to detention where he would be surrounded by them.
But his imagination supplied the rest of the threats. It created a Me vs. Them mentality in him: an emotional shield which also contibuted to the geek ubermensch syndrome, the part of him that professed superiority over his peers even as internal demons screamed inferiority. Naturally, viewing everyone with barely-veiled suspicion and even less-veiled sarcasm didn't exactly contribute to an atmosphere of friendliness. Meanwhile, the very people he could have been great friends with were the ones that threatened him the most, for they knew as much as he did about computers -- sometimes more. He couldn't let people beat him in the one thing he lorded over people, could he?
And throughout all of this, paranoia fed egotism, which fed isolation and rudeness, which fed more paranoia, leading to a vicious circle, a snake eating its own tail.
It wasn't until college that his attitude began to shift, and he finally began to realize that it wasn't him versus the world, it was him versus himself. He stopped assuming people were out to hurt him, and just assumed that people were people, and he was just one of them. It was then that he discovered: some people may really have been complete jackasses, but in the end, he had created his own hell.
He finds it strange to think about those times now, almost as if he's recalling a fading nightmare. He likens his state of mind back then to that of a dreamer, convinced of the reality of the illusion he is in. He just wishes it hadn't taken him so long to wake up.
The moral of the story: Think about what's making your life miserable. In the end, it just might be yourself.
Addendum: I'd like to recommend Templeton's brilliant writeup on the same topic, "Even though we don't believe it, low self-esteem is actually one of the most self-centered acts, not unlike suicide."