I can't say I've ever met any end-user, in 15 years of supporting end-users, who was confused by the concept of categorizing documents on their computer. These aren't techies. These are project managers, customer service reps, lawyers, nurses, file clerks, administrative assistants, and CFOs who organize things in a way that would make a "geek" blush.
What I have seen, however, is a lot of iterations of search implemented in Windows over that time that have varying degrees of reliability. I'll give the organizational and retrieval edge to these "confused" end-users.