I don't have a college degree. I made a deal with the head of the college math department that he'd sign me in to (senior level) Numerical Analysis (this was the early 1980s) if I taught myself calculus first; which I did. He had misgivings about this self-guided selection of study, and summed it up thus:

    How do you know what's important?

Now of course ML is all the rage, but that question has stuck with me. I still ask myself that question, and I don't always know the answer.