Feedback should be used to let others know how the seller/buyer conducted themselves. Many people sell an item. The buyer buys it and pays for it. The seller then does not bother to leave feedback until after the buyer has left them. This is the wrong way to use feedback. Once an item has been paid for the seller should leave the feedback, to let others know how the buyer paid, ie was it prompt, etc.
It seems that feedback is used in the wrong way so that if the buyer leaves negative feedback, then the seller will. This really bugs me.
PROVIDE FEEDBACK AS SOON AS THE BUYER HAS PAID.