Pie Charts Are for Thanksgiving (When Circles Make Everything Harder)

Dashboard review. Someone shows market share by product. It's a pie chart. You stare at it. Which slice is bigger—the 23% green slice or the 21% blue slice? Can't tell. You have to read the labels. Now try comparing to last quarter's pie chart. Which slices grew? Shrank? Impossible to tell without doing mental math. Pie charts force humans to compare angles and areas—our brains are terrible at both. It's like asking someone to build a car by eyeballing measurements instead of using a ruler. A bar chart would've shown the comparison instantly. But pie charts "look nice" so we keep using them. And making every analysis harder.