Haven't read this thread, but sort of chuckled when I read the title. They have a reputation...
Think of it this way, when I walk into an electrical supply house, if I get service at all they start slamming me because I am not a licensed professional. Wasting their time, using the wrong name for a part, placing a very small order while they are wondering if I'm going to burn someone's house down.
The owners of St Pat's were always polite to me - at least after they knew I worked in the same industry. It was always nice to see them when I needed a same day gasket or ferrule, etc. Wish they hadn't moved, now no local source for professional parts. Never needed to return anything, knew what I was there for, inspected parts before leaving.