Feedback about what you can improve doesn't necessarily provide you any feedback about how well you are meeting expectations. This is especially true of writing

Feedback about what you can improve doesn't necessarily provide you any feedback about how well you are meeting expectations. This is especially true of writing and other work that doesn't have a right or wrong answer. There are always ways to improve, there are always other aspects to consider. As a teacher, the author likely delights in finding students that are gifted, and finding ways to develop them even further, so she will always have some feedback to provide. Also, there is nothing wrong with a student simply wanting to learn material well enough to get a decent grade. All students have to take classes that go beyond their interests or even needs; it should be their choice as to which classes they want to be merely competent at and which they want to master.