How I enjoyed learning about that mainstay of modern approach aids, the Microwave Landing System!
What frustrated me more than anything was that the requirement to learn reams and reams of useless garbage pushed you in to a rote learning / QB based approach and blurred the lines between what was useless and the elements which might one day be useful. For me the exams just became a game to be passed with the minimum effort rather than an opportunity to learn and become a better pilot as a result.
I came to the EASA exams from the FAA system. Even though the FAA exams are much easier I learned a lot more from them as the content was relevant - and I had to know it inside out for the oral exam.