That's the thing.... Most people are basically honest and forthright. Because of the anonymity factor, eBay seems to be a successful avenue for scumbag lowlife to either 1) completely rip off the naive and usually inexperienced eBay'er and/or 2) just make life more difficult for the vast majority of honest eBay buyers and sellers.
I've been pretty fortunate so far, but I am skeptical in general of the intentions of people I don't know from Adam and that skepticism is reflected in how I buy and sell stuff. Usually the most frustrating thing for me is lack of communication by the other party.