I had no idea that LibreOffice can't be forced to recognize that a .txt file is CSV; that sounds annoying.

Watch out, though, for handling CSV files in Excel if you're using an encoding other than ANSI.

Excel for Windows does not correctly write UTF-8 files[1]

Excel for Mac lists 'UTF-8' as an import CSV encoding option but Excel for Mac does not import UTF-8 CSV files[2]

[1]Response from MS employee: "Unfortunately, not all applications can encode files in UTF-8 by default, and Microsoft Excel is one of them." http://answers.microsoft.com/en-us/office/forum/office_2013_...

[2]Response from MS employee: "Excel for Mac does not currently support UTF-8" -- despite UTF-8 being an option in Excel for Mac http://answers.microsoft.com/en-us/mac/forum/macoffice2011-m...