The one where the library the program needed had to be required from source, and the source had dependencies not in the distro’s repo. Flatpacs might finally be solving this, but for some reason Linux folks still think bundling a few hundred kb of libraries and dependencies with the program is a big nono, so software install is really really hard for anything not in the repo, whereas on Windows it just works.

If you only need Firefox and VLC, Linux is great. If you use a wide variety of programs, expect most to either not work, or only be usable as the Windows version through Wine.