The principle that I found to be most interesting and beneficial when it comes to my growth in the subject of information design is relating to the audience. Tufte references how chart and graph designers often belittle or insult the intelligence of the viewer. However, he claims this is one of the worst things we can do. It is important that we never underestimate the audiences understanding of our visual because our ultimate goal is to educate them on a subject, and not just to entertain them.
Notice the visual that I've attached above. Our attention is being drawn towards the man running up the bar graph. However, our focus should really be on the data that the creator is trying to teach us about. The visual is childish, immature, and takes away from the significance of the data.