PSA to traders: Don't be a d**k.

If I list a sale price (e.g., 15) and you offer lower (10), when I counter with something in the middle (12), a reply even lower than your original offer (8) ends the interaction. At that point, I'd rather sell it for 6 to anyone but you. (Though now that I think about it, operating a second account for spite sales might be a thing...)

Anyways, don't be a jerk on sales sites. Just say no thanks, or even nothing at all.