Sellers who won't leave feedback until the buyer does. I don't feel as appreciative of the seller if he doesn't give me feedback first. If I paid within a reasonable length of time and wasn't a PITA, then why wait to give me feedback? Even if it turns out that you are a terrible seller and you shipped me an item not as described, so I am going to complain - I still did everything I was supposed to do as a buyer so I deserve good feedback immediately after payment.