I don't know if this will help anyone or not. I, too, am annoyed by things being fixed that weren't broken to begin with. After trying to find the checkbox listed in several replies on this post, I was unable to find it (below). I only showed "Show recently used files", "Show frequently used folders", and "Show files from Office.com". After trying for too long to fix this, I was able to get it to work by doing the following:
In the lefthand pane in explorer, I right-clicked in the "white space". I saw the options: "Show Libraries", "Show all folders", and "Expand to current folder".
It appears that "Show libraries" is irrelevant. Checking or unchecking this doesn't do much on my end.
The "show all folders" box, however, changes the pane a lot. When I uncheck that box, it goes back to what I want to see, allowing me to see my quick access section and it appears to be "normal" on my end. When checked, it shows all folders and takes away the quick access section altogether.
In short, simply uncheck "show all folders" in the lefthand pane after right-clicking and it might fix the issue. Hopefully this helps SOMEONE.