What is the worst repair that turned out to be easy/inexpensive

Well, in that case, there’s nothing to complain about . . .

Not car related, but my garbage disposal quit working. The rotor would turn free, the built in breaker wasn’t popped, but it wouldn’t even try to run. I bought a new one and prepared for an afternoon of changing it. My first step was to unscrew the plate where the electrical wiring was–and found one of the wires had come out of the wire nut and was just hanging–the previous owner of the house apparently wasn’t the most competent electrician as I had this happen with the kitchen light fixture too. 5 minutes and it was back running.