Welcome to my world
I think most people lurking here have no problem understanding RC, because we all understand the fundamental blocks that go on behind the scenes.
I would say the bulk of our end users dont. They just want to read email, and are struggling to understand how things work. Especially modern UI elements like dragging and dropping are daunting. They just dont even begin to think about it. Once we explain, they go 'oooooohhh, how pretty'. But to get them to that step without hand holding is tiring.
Also, some of the smaller icons take a while to find for many users.
I have a working beta version of my UI help plugin. I can try and patch it up and release a beta today if you think it could help you. For now it only shows help for the mail interface though. (not addressbook, settings, etc)