I think a huge problem is that many people are scared by complex numbers and avoid them completely, thus avoiding and never understanding complex AC analysis... which in turn is pretty much the key to really understanding how linear systems, filters, amplifiers and so on work, why they are doing what they are doing, why they are stable or oscillating and so on.
And honestly, I avoided that part of "EE", too, until I had to do it for my studies. But now I can only recommend to study that part, because it is really like an enlightenment. And not as complicated as one thinks, in fact, complex analysis makes everything much simpler compared to solving systems of differential equations, which are ... much harder.