The problem with pie charts is that it's too easy to use them in a wrong way. I would say the only scenario when a pie chart might be a right form of data visua

The problem with pie charts is that it's too easy to use them in a wrong way. I would say the only scenario when a pie chart might be a right form of data visualization is when you need to display shares of two, maximum three, components of a total. It means 2-3 data points only. Trying to use pie charts for anything else will quickly degrade readability. More data points, day-over-day comparisons, variations with the circle size, grids of pie charts -- all makes things worse.