To protect your spreadsheet, Excel proposes the following options:
You can unlink a chart from its data ranges and produce a static chart that remains unaffected by later changes in the data.
Using the Hide command you can hide the data and formulas from "inquisitive minds". But some of them still can use Unhide command. Nevertheless you can completely hide Excel spreadsheet so that it will be needed some VBA programming to unhide it.
The Chart toolbar is a context-sensitive toolbar that appears when you click an embedded chart. Chart toolbar gives you control on chart type, data ranges, legends, etc.
Use COUNTIF if you need to sum values for a particular person or other criterion.
Use SUMIF if you need to sum values for a particular person or other criterion.
If you work with the same workbooks every day it will be helpful to open specific workbook files automatically whenever you start Excel. Any workbooks placed in the XLStart folder open automatically.
In some cases you may want to sort your data in non-standart ways. For example, if your data consists of month names, you usually want it to appear in month order rather than alphabetically.
You can make your Excel spreadsheets more appealing by choosing graphics file to serve as a background for a spreadsheet similar to the wallpaper that you may display on your Windows desktop.