When the last bunch mugs came out of the bisque kiln all I could say was, "Oh Sh$%t!". The slip trailed dots were supposed to be white and everyone of them was blue. I had even emptied my slip trail bottle and refilled it with the fresh batch of white that I had mixed the day before. The mistake came because I had also just slip trailed an order of blue dotted flower mugs and left that bottle next to the white. They were even LABELED and I still screwed up. In the end I decided I like the dark blue against the lighter blue underglaze.
Some mistakes do turn out ok.