Or a service writer in a dealership more concerned with impressing the customer than providing a description of symptoms. 99% of the time their written explanation of parts to be replaced was wrong and the Bonehead Service Manager hadn't a clue when I complained about the questions going nuts and asking why the service writers "analysis" differed from the actual repair. Boy, that nuthouse did not last long.
Like RV customers who drove in telling me how to fix their rig. If I informed them that diagnostics come first and they continued to argue it resulted in a .....
"Hit the road, toad"
Because people like that turned out to be the first ones to telephone the Department of Consumer Affairs.