Growing up I found Mathematics difficult to grasp for various reasons. One of them required mental gymnastics of "hidden" rules and exceptions to the rules. There would always be rules that were often forgotten. And one of the bigger problems I had was forcing myself to practice these exercises. In order to store this information one must actually practice these problems many times to have it lodged into your brain for later use. Being a kid made it even more of an obstacle since I always wanted to play outside or hangout with friends.
It seemed that mathematics required more of my time than any of the subjects. So wouldn't spend the necessary time needed to actually store it in my head. Later in life, I realized how fascinating math was, and fell in love with it. Even though I am still not good at it, it's fun to solve puzzles.