My kiln's controller failed right before a big show, turning a planned production week into a frantic repair job.
I had to source a replacement part from a shop in Asheville overnight, which cost me $220 and a full day's work, but got everything running with hours to spare.
Oh man, a rogue glaze fire is the worst. I had one where this beautiful blue drip glaze just decided to run like crazy. It fused three mugs to the kiln shelf. Took me hours with a hammer and chisel to get them off, and the shelf was ruined. That batch was a total loss. Never trusted that glaze recipe again.