In this section, we will highlight a few example cases where a bad design of the visualization tends to influence the judgment of the reader on the reality of the numbers.
The following chart displays the evolution of Daily Active Users (DAU) on a timeline. Take some time, and look at it carefully:
As we can see, the evolution seems to have lots of variations, and the curve also has a worrying decrease at the end of the month. Now let's have a glimpse at the same chart with 0 as a starting point for the unit on the y axis:
It definitely does not look so frightening! Though ...