eBay - let me list unfavourite sellers
Ok, so there's a million things to fix about eBay, and as I noted before my top beef is the now-common practice of immense shipping charges and below-cost prices for products -- making it now impossible to search by price because the listed price is getting less relevant.
Here's one possible fix. Just as you can have a list of favourite sellers, allow me to add a seller to my list of blocked sellers. I would no longer see listings from them. Once I scan a seller's reputation and see that I don't trust them, I don't want to be confused by their listings. Likewise if I want to block the sellers who use the fat shipping, I could do that, so I could unclutter my listings. That might be something to make a bit more temporary.
Ideally let sellers know they are getting on these lists, too. They should know that their practices are costing them bidders.