The Tukey mean-difference plot, also called the Bland-Altman plot, is a recognized graphical tool in the exploration of biometrical data. We show that this technique deserves a place on an introductory statistics course by encouraging students to think about the kind of graph they wish to create, rather than just creating the default graph for the variables types they have. This graphical technique is described, and two examples are presented: one dealing with official agricultural data of Poland and the other one with an experiment on anorexia. Our opinion is that the plot is so easy and yet efficient in visualizing paired data that it should be included in statistics courses to support understanding and interpretation of data and their analysis.