I think the worst thing about it was that you could never just chill. It was friggin' relentless. Every day in high school's got a very do-or-die thing going on, for some reason, while at the same time feeling like the lowest-stakes thing possible. It was like stress for the sake of stress. Meanwhile those days are relatively rare in college and real life. Certainly not 5 days a week, every week, unless you seek out jobs like that. Granted the lower end of the job market's a lot less flexible and easy-going than, say, software development, but even that's usually not as bad as high school, which is pretty damning.