Yes, any task you have to read documenation for is, pretty much by definition, not a "just works" task. Of course, 'using' an operating system has so many aspects to it that your point is pretty nonsensical. In any case, we were talking about installing the OS, not using it.

That said, there are several OSes out there that have plenty of users who never read the docs for using it. Android, iOS, OSX, and Windows all have teeming masses of people who are able to use them adequately without reading documentation (just ask someone who's worked a support desk).