I just think it's better to do work and be annoyed by it, as opposed not doing work and freaking out because you don't feel prepared for a test.
Sure, last year in Modern World we groaned every time she said "reading" (or "Holocaust", but that's another story), but not only did everyone do extremely well in the class, people were actually engaged and interested in what we were learning. People who would never talk would actually get involved in discussions and when you have an engaging discussion, you learn even more. Which is good for everyone! I don't see the harm in busywork unless it's extremely frustrating (as in, the directions don't make sense), not because it takes an hour and you feel like you didn't gain anything. After all, what are you going to do with that hour? More schoolwork? Play video games? :V