Books and CDs.
For a while, I started getting hardcover book orders (which are like hen teeth once in a blue moon order) packed loose in those bubble wrap envelopes. This minimal protection invariably allows dents and bends and pages and covers damaged which are clearly visible when you examine the book, which is hard not to do when you're reading it. Does not affect it's utility, but it would be nice to have a new undamaged book. Last few have been received in boxes (which I requested many times when I complained upon getting them in envelopes) with ample bubble packing so that they were in pristine condition.
CDs seem to be hard to get without damage to the jewel case. Cracks in the case and damaged case hinges are common. Knock on wood..., the last several have been fine.