In a former life as a sales / counter guy at a chain of tire & service stores here in the USA, it was sometimes surprising how many people did not know what kind of car they drove. Sometimes the year would be off and it would be a major issue getting the information corrected (ex: 1986 Olds 88 is much different from 1985 model).
But my favorite was when a customer came in and was adamant that he owned a 1987 Buick Oldsmobile. "It's a BUICK OLDSMOBILE, I'm TELLING YOU, that is WHAT IT IS". Customer then threatens to waste time by digging through the pile of trash in the passenger seat floor area for the title, I figure out what it is by walking out and looking at it for a few seconds.
Still kept him calm enough to buy two tires for his 1984 Olds 98 Regency, the key being verbally agreeing that Buick built all Oldsmobile cars in 1987 like he was telling me they did.