Why is the 'include zero on y-axis' option disabled by default?

The option 'include zero on y-axis' is disabled by default primarily to prevent misleading representations of data that could exaggerate perceived trends. When a graph does not start at zero on the y-axis, it can create a visual impression of dramatic increases or decreases in the data, which might not accurately reflect the true scale of the changes. This practice can lead to misinterpretation for viewers who may not realize that the graph is truncated, potentially causing significant misunderstandings about the data's implications.

For instance, if a graph shows a small increase but is set up in such a way that it doesn't include zero, the visual effect can exaggerate the increase, suggesting a much larger change than actually occurred. Thus, keeping the y-axis layout in a more conventional manner helps ensure that viewers can interpret the data more accurately, promoting integrity in visual data presentation. This focus on promoting clear and honest graphical representations is why the option is not enabled by default.