This morning I had to fill the coffee urns with hot water before brewing the coffee, so that the urns were warm enough to keep the coffee warm. So I filled 3 of the 4 urns and set the coffee maker up to brew a pot of dark roast. I shoved the appropriate urn under and started to brew the coffee, then walked down the back and around the corner for a minute to attend to something. When I got back, the coffee was all over the counter and the floor. Took me a while, but I figured out what was wrong: ALWAYS empty the water from the coffee urn BEFORE brewing the coffee!
What a start to the day!