Ever had to look at a data visualization while you were in a lousy mood? Chances are you were more likely to make an error in visual judgment than if you had been feeling more cheerful. New research suggests that putting users in an emotionally positive mindset improves their accuracy in interpreting data visualizations. So even if your company publishes only the occasional graph, provoking a positive emotional response in the audience might just help you get your data across more accurately. Moreover, as research in this area grows more nuanced, companies producing visual analytic tools and products may be able to enhance their effectiveness by designing with emotion in mind.