Lots. Just this year: Opened "new" Makita power-tools where I can't be sure if the batteries are legitimate or knockoffs or old/refurbished ones in their place. Cracked sink that is still pending return after two weeks. Counterfeit Whirlpool filters for my air filter. Floor oil that was opened, spilling a little, and shipped in a bag alongside its non-spilling counterparts.

The only quality items I'm willing to order from Amazon now are small things like pens, and commodities. No more high tech stuff, no more camera equipment, etc.

> Has anyone had any issue with "Sold By X, Fulfilled By Amazon"? That usually works well for me.

That's actually the worst, since that opens you up to getting counterfeit items from reputable sellers, due to Amazon's inventory commingling.