Cat diagnostics
About 40 years ago I use to repair data loggers that recorded everything on cassette tapes, a typical problem was that the tape motor would have problems and start getting noisy, so that was always an easy fix once you turned it on and heard the problem.
On night I woke up about 2am, dreaming that I'd been trying to fix a unit and each time I replaced the motor the problem kept reoccurring, so frustrating that I couldn't fix it ... when I work up I discovered that our cat was sitting on my chest purring! Problem Fixed!!!!!