>Thanks - so no matter what, when entering a date in a spreadsheet, you allllways have to enter the / / to get a proper date...

As Thomas said, you may have to use the appropriate separator for your regional settings. Anyway, Excel, as LibreOffice, and Google Sheets, they all make an extra effort to parse correctly whatever you may enter as a date. For instance, if you insert Jan/2016, you'll get back a date...