Especially recent with the DefaultTrust changes, there's a vast network of users that have "trusted feedback" and thus it's not a matter of if someone will have negative feedback, but when.
I still remember when I got a message from someone complaining that it wasnt fair I had such an extensive and flawless trading history. Ever since then its been one attack after another. I think to a certain extent, if you havent gotten a negative trust rating, you probably havent done anything of value. Sometimes though, like in Vods case, people bring it on themselves by spreading lies, abusing the system, and acting like a moron.