jilleduffy, I call this one
MISTAKES WERE GLAZED
(My pottery names are getting to be a little too much like Bob's Burger of the Day.)
A handmade mug turned so you can see its bottom; there is an ugly excess of glaze from the mug that has pooled and dried around its base, causing sharp messy bottom that makes the mug unusable unless ground away with special tools. You can see air pocket and bubbles in the excess
A handmade mug in a shimmering opalescent glaze on a window still with potted house plants in the background.