|Learning Excel isn't necessary to using the Excel Diet, but the better you know it the more productive you'll be in work and in life. |
It really is an amazing tool that has much hidden under the covers in it's programming language called VBA (Visual Basic for Applications).
If you're interested in learning more there is plenty of content on the internet to help you.
I have a site ExcelBeginner.com which is the start of a book I'm working on to teach Excel.