My worst version of this was in third grade where we learned our multiplication tables. Our teacher had us all make multiplication flashcards. 1x1 up through 12x12. She then assigned us to spend a certain amount of hours practicing the flashcards, including some log and parental sign-off IIRC. A card might have "3x8" written on one side, "24" on the other. Practice and drill until you memorize them all.
Well, the problem I had was that I memorized my times tables in a fraction of the time we were required to practice. I ended up getting in trouble for not having enough practice hours - even though I was acing the quizzes we were getting. This wasn't even about showing your work, as this was a rote exercise in memorization!
But the teacher thought that it took X number of hours of practice to learn your times tables. That's what she assigned, and nothing was going to change her mind. So I sat at home pointlessly practicing the times tables I had already memorized, instead of doing something fun or even moving ahead to more advanced math concepts.