I haven't had the experience of negative feedback in a long time, but haven't done much buying or selling in a long time. I appealed to eBay regarding a negative feedback that after providing the information of the circumstances three times the eBay customer service slugs couldn't figure out the issue. Anyway not long afterwards eBay scrubbed all negative feedbacks, at least from my account, apparently as a forgiveness and reset sort of program.
I've been scammed by both sellers and on one occasion a buyer, but my experience with feedback is so jaundiced I just passed it off as the hazards of doing business with people, and felt no obligation to post any comments. It is clear that some people take feedback very seriously and need to calm down.
I don't feel obligated to leave any feedback for a transaction that is completed without any problems, that's the way it's supposed to go. I get "reminders" from sellers pandering for feedback, so I guess some people like to have their egos massaged, and the more they insist the least likely I am to oblige.
Lots of collectors like to complain about eBay calling it "ePay" which I take to mean they think they are being charged exorbitantly. I was collecting long before the internet and eBay, and dealer/sellers were just as exorbitant in their prices as they are on eBay. I suppose the sniping game is collectors way of try to get a better price for material culture militaria. EBay provides a whole different convenience to traveling around to gun shows, and mail order businesses.