I always found highschool extremely boring and socially uncomfortable, with nothing of any value being taught. I would occasionally get in trouble simply for correcting teachers' mistakes, until I had enough and began to frequently disrupt lessons for my own amusement, from whistling and swearing in class, to letting off smoke bombs and setting things on fire, until I eventually discovered that it was more fun to just get drunk in school with the other "bad" kids and wander off into town whenever I pleased.
I was permanently expelled after being temporarily suspended too many times, for what was seen as persistent bad behaviour, and truancy.
After that they made me go to a special education unit, where a taxi picks you up every morning, and then they lock you in the building all day. This was supposed to be where all the "bad kids" go, but I never had anyone try to give me any trouble. The problem was that everyone was always together in a group, in the presence of multiple teachers, and there was nowhere to take a break away from the constant social interaction. I couldn't eat lunch at all, not even one day. Too crowded, practically claustrophobically packed in. Yuck.
After a month or two, I stopped getting in the taxi in the morning. Eventually, it just stopped coming, and that was that. No more school. I was always considered to be intelligent even despite my behaviour, and all throughout school I was given work which was years ahead of what the other students were doing, but when I left I had no qualifications of any kind.