I agree, and it's the same for all the engineering courses I have done. I could explain almost all of the concepts for a lot of my courses with hardly any study

I agree, and it's the same for all the engineering courses I have done. I could explain almost all of the concepts for a lot of my courses with hardly any study, but 90% of the exams I do are (essentially) just solving problems, and being prepared for that often takes a lot of practice in my experience.