Yet another day of bull$stuff at the parts store

It's just incredible the stuff these people do not know, the basic hardware and fittings terms and types of bolts

I was in a local fasteners store. This is what they DO. They sell bolts and nuts. I had a common, ordinary American cap screw that was EITHER 9/16 or 5/8 SAE thread I simply had not measured it. Here's what I KNEW

I knew it was larger than 1/2. I knew it was SAE that is common fine thread, and I knew it was NOT metric. So I told this meathead.

"That's either 9/16 or 5/8 SAE I'm not sure which. I need a Nylock nut."

So he's screwing around with digital calipers and thread gauges and frowning and conversion charts and I finally ASKED him

"What's the matter?"

"I'm making sure it's not metric"

"I already TOLD you what it was. It's either 9/16 or it's 5/8 AMERICAN. It's FINE THREAD. It's SAE. It's a COMMON bolt. It is NOT METRIC. There is a REASON I told you that. I COULD have measured it but I didn't think I needed to"

My Goauwed. You'd think I insulted his wife. You'd think I maybe might have summoned the Devil himself from the under reaches. You'd a thunk I tried to rob the joint from his attitude.