Outside of STEM classes, the only thing I learned that was relevant to my career was from my Technical Writing course, where I learned that people in charge can be capricious and screw you over in the process. The teacher didn't like me, so he consistently gave my work mediocre scores and couldn't quantify anything about the work or the scores.

Even some of the STEM classes were a waste of time, especially the Computer Science classes where the professor would grade people on attendance and random minutia.

I ended up just learning computer science on my own off of Wikipedia after I graduated since I couldn't get a decent hardware design job with my Electrical Engineering degree. It only took a couple of months, BTW, to get from the point where I was just playing around with JavaScript to where I could pass a coding interview laden with data structures and algorithms.

If I could go back in time for a day and talk to my former self, I'd tell him to just buy some used physics, math, and computer science textbooks, then spend six months couch surfing, partying, and studying on his own. Then he could go find a CS job and start making money right away