I find that I am usually quite good at applied math, and enjoy it. I am taking a course currently that is split into two parts, Vector Calculus and Complex Analysis. The vector calculus makes sense to me and I can see how and why it works, and I find it interesting and enjoyable to learn.

On the other hand, I spend quite a bit of mental energy wrapping my head around the hows and whys of the more abstract complex analysis. I am not sure if I enjoy abstract math or not in general because I do not understand it as well. So, my question: Does anyone have any recommended resources for learning (any) abstract mathematical topic from first principles, that explains reasonably well what's going on with the math, rather than just how to do it?