Which is another way of saying that the "advanced" subjects (vector calculus, multivariable calculus, fourier transforms) really aren't that bad if you're prepared to put the work in.

Probably because most people choose to study what comes easy to them.

I think the key is finding an intuitive way to grasp the subject matter, and then it doesn't feel like such a grind.

If material like this had been available 20 years ago it would have made a huge difference.

https://youtu.be/spUNpyF58BY