When I was a senior in high school, I needed one more science credit for graduation, so I took Human Anatomy. It was taught by a young hippie (it was the 70s), who also taught the exact same course at the local community college.

It was a great class, with lots of cool labs, experiments, and dissections. We had to memorize every bone, and every muscle. It was one of the hardest classes I've ever taken, but also the most fun.

That class was filled with future doctors and nurses, so none of them were whining about how they'd never use this stuff. But I wasn't on a medical track (I was a music history major), and I could have probably said that (I didn't), but I have used the knowledge I gained in that class literally every single day of my life, decades later. Easily one of the best classes I took in my entire life.