Criticism of designs and ideas is an important tool in art and design-and it can also be used to great effect in visualization teaching and research. We describe the basics of critiquing in visual art, where the goal is to teach the students to see and to articulate their ideas and concerns. The use of criticism in teaching shows how this concept can be applied for more active classroom interaction and discussion. In response to a visualization critique example, we also offer a critique of critiquing: what are the pitfalls, when can criticism actually harm the design process? Finally, we argue that critiquing strengthens the theoretical foundation of visualization, and is really only an extension of an activity we are all familiar with-peer reviewing.