The other reason to not use Excel for stats? It's virtually impossible to reproduce your work unless you documented every step in some other format. Excel is easily one of the worst tools you can use if you ever need to refer back to/redo your original work at any point in the future or if you need to be able to validate your result with any confidence. Yea I know there are some people who are freaking magicians with VBA who can "fix" many of the problems listed, but that doesn't absolve excel of its statistical sins.