Microsoft Office. LibreOffice is pretty good as a standalone product, but when I used it regularly I had nagging document formatting problems when exchanging files with my work colleagues.
If you depend on a software that is available for Windows only, you're on the borderline whether you're actually using it by choice or not. Especially if the software is Office. At work I have to use Outlook for corporate communication so I run it Windows in a virtual machine. The tools I need for real work are Linux-only (and require native HW access), so this is the only sane choice. Of course, this means I have to have a license for Windows.
Now Visual Studio is a different beast. Comparative tools are definitely available on other OS'es, but many VS users have a preference.
Visual Studio.