A good understanding of the basic concepts behind the workplace environment will lead to greater user satisfaction and should help reduce their need for support.
It is important that users understand not just the techniques used to interact with the Workplace Shell, but also the objects that the WPS uses. They may think that, since they make a copy of a file using Ctrl-drag but a shadow copy using Ctrl-Shift-drag, then Ctrl-dragging a file will always make a real copy, no matter what kind of object the source is. Of course, that's not how the WPS works; if you copy a shadow, you get another shadow.
Shadows can cause other problems for the inexperienced user. For example, if you have a user who wants to copy a file to a diskette, they will not differentiate between the real file and a shadow, and will therefore fail to understand why the WPS won't let them drag that shadow onto the diskette icon. In general, it might be better to remove the diskette icon from the desktop and let users work with the Drives folder for all their file system interactions.