A while ago, I installed an electric furnace for an old guy. He was convinced that the blower was moving so fast that it was somehow "quenching" the heat of the furnace. He actually opened up the compartment containing the elements to show us that the coils weren't bright red like they were "supposed" to be. He constantly di@#ed with the thermostat trying to get hotter air.
Guy drove me absolutely insane. I am always scared to install equipment for old people.