Ehhhhh... there is such a thing as too old. Or at least too set in one's ways and willfully ignorant.
A friend of mine once rode his Suzuki motorcycle to an Ace hardware seeking an M6 screw for a cosmetic panel. For his Suzuki. Which is a Japanese motorcycle, made in Japan, where they have these things called millimeters.
The ancient doddering git presiding over the fastener section knew nothing about such newfangled foolishment as "metric", and didn't want to hear anything about those damn made-up commie "milly-meters". In the end he sold my friend a couple of 1/4" fine thread screws. With a thread pitch of 25 TPI, these do indeed look a lot like M6x1.0 threads (an inch is 25.4mm). If you're persistent, you can even thread them in, a little, and when you remove them again, the threads in the machine will be nicely hogged out and unable to retain anything.
That all took an unreasonable amount of time to figure out, and a fair bit of effort to correct.
I know they're trying to be helpful, but when I'm looking for nuts and bolts I'm generally one of those "I know exactly where to look, thanks" (AKA, the polite phrasing of "stay the hell out of my way") guys.