Once I started to really want to understand and write audio processing code, I suddenly had a framework to not only care about Trigonometry, but to actually apply it and to have a tool that would validate my understanding of it. That short feedback loop got me through the subject incredibly quickly.

I was completely blown away when I started reading some Linear Algebra material because I realized that I had essentially been doing it for years without even strictly realizing it. The subject came to me very quickly because I already had a solid "mechanical" understanding of how to implement systems utilizing a particular subset of it.

I think passion for the deeper maths is something most people just have to discover through application, and there just happen to be a rare few who discover a pure love of it very early in life.