Theory

User: I want to export a report to Excel.
Me: Oh ok, well, on Print Preview, simply choose File > Save As > Comma Delimited File.
User: That's not Excel.
Me: Actually, a comma delimited file is usually registered as an Excel file type, so Excel can open it.
User: So, in theory, I'll be able to open this file in Excel?
Me: Yes sir, provided that .csv is registered as an Excel fiel type, you can double click the file and it will open in Excel. If its not registered to Excel, simply start Excel first, then choose Open, then select ALL FILES and click the .csv file you created.
User: So, in theory...
Me: (I'm not quite sure you know the definition of the word "theory")