I got a few pages from AARP that say "Must Read". I didn't notice the label at first, but I just wasn't interested. I take a limited approach to telling people what to do. I take a very limited approach to telling them what they must do. In college and grad school teaching, I assume that the students want an education and I want to do my part in providing some of it. My experience is that very rarely is something actually essential. Sure, for most cases, reading a particular document will normally be of assistance. But if the instructions are set too high and make too tense an expectation, they can lessen the degree of comprehension and retention the document produces.
In the case of a student who is already expert in a given matter, it can be better to leave things to the student's judgment as to whether a particular source is a help or not.
I have seen rising levels of threat and requirement before. In fact, just in the case of citing books that have mattered to a person over a lifetime, you can see related phenomena. "Book X is my favorite novel but Book Y is an ever better book." It can help to get away from more strident language and simply say that books X and Y have been wonderful and helpful. A person trying to convey just how wonderful a book (was for them, at that point in their life) can be almost visibly trembling with the tremendously high quality of that book. You can feel their attraction to command format: "You MUST read that book!" Sometimes, I feel their need and read the durned book. I didn't like it.
