I took a linear control systems class in college, probably at the peak of my mathematical abilities. I hadn’t yet forgotten the fundamentals of Laplace, Fourier, and solving differential equations. Not to say I was some math wizard, but at least the prerequisites were fresh on my mind.
It was fascinating, but I just couldn’t grok it. Whatever weaknesses I had in the relevant maths, that class just seemed to amplify it x10. I still wish I could have absorbed more of the knowledge