I have now spent the last 20 years of my life in the formal education system. This includes all kinds of schooling: private school, public school, a self-directed learning high school, undergraduate studies, and most recently, professional school. I have 1 year left to go in medical school, but if you count residency as a formal education, then I actually have at least another 3 years to go (assuming I do Family Medicine residency, which is the plan).
Every student at some point in his or her life comes across a school subject they hate and asks:
Why do I have to learn this? I'm never going to use this again.
Usually parents and teachers say something like “you might not understand now, but someday you'll see why it's important”. Sometimes this is actually true. But other times, chances are your parents and teachers are thinking the same thing you are.
So why are there all these different subjects that often don't seem to really matter?
The main theory that comes to mind is to expose students to a variety of subjects. How do you know what subjects would interest you until you try them? It's like trying new food – you're missing out on a ton of great stuff if you never try anything new.
I think this concept is sound on a theoretical level. And so it makes sense that not every student is going to like every subject out there. You might try Science and hate it, and never want to do it again. On the other hand, you might try Science, love it, and become a scientist.
Both outcomes are useful: if you like the subject, you are closer to finding a career or interest; if you don't like it, well at least you can rule stuff out.