For me it was getting up at 7AM, which never happened. Missed a lot of school, ended up dropping out (apart from when I had an Engineering or Technology class as I had projects to do, 2 days a week) and doing most of the exam myself. Suffered a lot from being late for school and ended up even being suspended for 2 days for leaving school early like 40 times(wasn't bad :D).
But my parents were never happy so that caused a bit of stress at home at times.
I also ended up getting way less points in my exam than if I were to stay going in, but that didn't really matter because my college course had relatively low requirements anyways. Still overshot
the requirement by 100 points too. (The most points you can get is 600, my course was 285, I got 385, should have got ~520, if I went in)