The other aggravating thing is when (not saying you particularly) people judge bolt size by the wrench size. I've seen 1/4-20 bolts that take a 5/16, a 3/8, a 7/16 and sometimes even a 1/2" wrench to work them, and some are even Phillips or straight slot or even Allen head ... all are a 1/4" threaded shank.
So many people think a 1/4" fastener is really a "7/16 bolt"