A critical appreciation is a written work that examines and evaluates a piece of literature from a discerning and critical point of view. Basically, it's something written by a reader that explains, in detail, what was good and/or bad about a piece of a literature. It could also explain why the reader liked or didn't like that particular piece of literature. For the tale told by the Wife of Bath, you can't simply say that it was good or bad. You have to explain why you think that, and providing examples is also key. Your critical appreciation might examine the themes of the story and how they apply to the Wife of Bath herself. You could do a character examination of any of the characters in the story, or you could compare any of the characters in the story to the Wife of Bath. Perhaps your critical appreciation could turn more personal. You might state that the tale is terrible, because it teaches bad or incorrect morals. Your task is to then defend yourself with a close examination of the text. The opposite could be done too. You could claim that the tale is one of the best of the tales included in Chaucer's text and explain why it is so well written.