Depending on data, Excel, OpenOffice.org Calc, Google Docs spreadsheet, which are the most popular spreadsheet applications, scale chart axes differently by default.
Below are examples. (twitpic.com)
Note that the vertical axes start from 0, 75, 80 depending on the values in the charts in Excel and OpenOffice.org Calc. Google Docs' chart has its vertical axis from 80, not zero.
The problem is that the mysterious feature may lead to chart junk because the axes don't start from zero and are misleading.
I couldn't find how to fix this by changing default settings with these applications.
So I'm working on Excel macro which scans all the bar/column charts in the current book and make their axes start from zero.
You can see the source code of the macro at Gist.
I think the best solution is that Microsoft fixes this problem, because it is the most influential company in the spreadsheet software industry.
To Microsoft: Please make the default settings of bar/column chart axes start from zero by default.