There's two sides to it. I had a perfect eBay record until one seller had issues with his payment system (initially tried to ship to a non-verified address), I emailed him, he replied and I followed his instructions, completed the transaction, and the successful transaction shows up in my history. However, he never cancelled the locked up transaction and gave me a non-paying bidder strike despite eBay mediation, a full six months after the transaction was initiated. So my eBay record is permanently flawed because of one seller.

And I was screwed on a transaction, seller took a Postal Money order but never shipped the package, closed his eBay account, and failed to respond. eBay says tough luck. And because the seller closed his account, there is no way to leave negative feedback.