It was probably due to your education - specifically learning by rote. The person who decided to teach mathematics by rote needs to be assaulted. It was not until higher levels of education where I had someone properly explain the concepts and give me the tools to visualize the maths that I became able to actually understand. After that, honestly? It was kind of easy. I do think that it may have something to do with the way my head works. Let's just say that it is not normal (I don't think - I used to think it was) and you probably would not be comfortable listening to my thought process.