The insult of insults. I was showing a bunch of functional ceramics at a show (teapots, cups, dinnerware sets, etc.). I had them set up on bricks from a salt kiln I'd disassembled that had lovely rich colors from the salt glazing. Also, as a backdrop, I had a large piece of copper wound through the backdrop that I'd left in the elements for about two weeks, then buffed in certain areas and taken to a paint shop and had clear coated.
A lady told me while she thought my pieces were lovely, she'd give me the price of all my wares but only wanted the bricks and copper plate. Hell, I was a starving college student so I took her up on the deal. It paid for a full semester.
eventually, I did sell most of my wares and at the end of the show, she showed up in her nice new truck and hauled away the rest.