Learning how to type.

You either had to take typing, or some other class that I can't remember during my junior year. The other class didn't appeal to me at all, obviously as I cannot even remember it now, so I took typing. By happenstance my best friend was in the same class.

The class taught me a skill that I use till this day, some 38 years later.

My locker combination

Leaving a cutting knife in a sink with soapy water is the best way to fail the exam and cut yourself.

SOH CAH TOA in trigonometry

That nobody gives a shit about you, especially if you are in any way not mainstream, and they’d rather you not exist than to help you.

The cell membrane is a biphospholipid layer that's 7.5 millimicrons thick.

Calculus. That is the first thing that comes to mind.

Don't let them search your car even if you know there's nothing in there.

I learned about 9/11 because it happened when I was in high school.

"Basically nothing"
Felt mostly like a waste of time.

That high school was nothing like what was depicted in Grease.

History.

I had a great teacher and it was my favourite subject. I wish I could've demonstrated more gratitude instead of feeling the need to act like I didn't like it for fear of being bullied about it by my classmates, and wish I applied myself more and wasn't held back by ADHD, but it was a well-earned B on the exam.

I didn't know it then, couldn't have, but it taught me critical thinking then and there through the simplistic exercises of looking at old political cartoons and recognising the biases and influences there and to see symbolism and metaphor and allegory not just as purely confined to the "entertainment art" realm, but as a core part of communication in general and a tool wielded in politics and propaganda.

Good timing too, that was during gamergate, two years later it'd be 2016 and the first time I would be exposed to targeted propaganda that had any chance in earnest. Growing up in Russia I had already known not to trust, but it was easy not to trust the weird revanchism of a country I never liked that much anyway, compared to loud young and relatable people on the internet, which was my one and only space to socialise back then due to being bullied and ostracized a lot in school.

Not sure if it counts as "High School" though, idk the American school system, I did History for what used to be called "GCSE" in the UK, it was year 11 for me, out of 13 years total in school.

@ReanuKeeves Punching a teacher to the ground is always a good idea.