I've left approx 25 negatives over the years, and I've never received a retaliatory negative feedback. Perhaps "bedside manner" and advance warning of the negative, in a non-emotional way, have something to do with it.

The thing to remember about eBay's feedback system is that it is NOT eBay's system, it's ours. It's a user-to-user thing, and we all know some users can be very childish and petty.

eBay is very much limited by law in what they can and cannot do in altering or removing feedback comments, and even if they could intervene, I don't think they would ever put themselves in the position of deciding who the best liar is.

As far as the system being "totally worthless", I currently have 6816 positives and 1 negative, and I really don't think that's worthless information, do you?