I remember "ignoring" my statistics class in undergrad. What I mean by that is I never attached real importance to the subject matter. I did enough work to get through midterm and final exams, but not much else. The result is that none of the content ever stuck. I felt lucky that I was able to cram sufficiently and pull off B+ or A- grades. In retrospect, I recognize that I could have done a much better job in absorbing the material. Not only in statistics but in other subjects as well...
Back to re-learning.