It would take pages to explain all kind of different situations. I once bought a magazine for $2, then decided that it was not worth it, and took me at least 10 mails -no exaggeration- to convince the seller that it was perfectly right to pay him $2 so he can either relist or throw it away, while he insisted I had to complete the transaction. I have had carbs put inside a box, with no padding at all, miraculously arrived safe after having met each other for thousands of miles of traveling. I have had a book described as "like new" arriving not only wet stained, but actually damp! It took me four mails to make the seller admit he unadvertedly let it fall into water after he listed it. It took almost three weeks to arrive, main reason he waited for it to dry but he couldn't hide it. Another book described as "new" had not only water damage, but also mold in pages. I got some discount from it because I didn't mind, but what if you want the book in perfect condition? You never recover the shipping costs. Even when I have been ripped off with postage I have never given any negative feedback because it is useless, but most of the times, with communication, I have got a refund to balance the situation.
Actually, I don't throw anything away, but give it for free to friends and relatives, and I know they will pass the items. That way I can get something for free too. If eBay evolves into a place for megasellers, it's deemed to disappear, because mega-sellers never sell rare stuff, and if they sell it they know its market value, so there will be nothing you can't find anywhere else. The beauty of eBay is that you can get your personal "rosebud", something you would pay a kidney for, for a song because it is almost worthless to somebody else. If it becomes a regular shop there would be nothing interesting in it.