Different operating systems give you different degrees of freedom, different degrees of access to knowledge of ???what is inside???. And, what is more important for a non-technical user, they give you different user interfaces.
Windows users are used to having a panel at the bottom of the screen, window control elements at the right side of the window, the Windows Start button and so on. If you see something like the modern design of the Unity interface, nothing is the same as Windows. It’s a steep learning curve, isn’t it?
To ease the transition from Windows to Linux, there are different interfaces available ???on the market???. KDE is usually considered as the most ???ex-Windows-user-friendly???. But there is a team which decided to give users another choice. This is the Zorin Team.