I work at an auto shop as a service advisor, we're open Saturdays but generally pretty slow, mostly calls to book in appointments and handle oil change traffic or general questions from drop-ins.
I had a pleasant and very short exchange with a customer just a few moments ago - relevant, I'm a young woman in a male-dominated field.
OG - old guy, pulls up in an older truck (relevant).
Me: "Hi there, what can I help you with?
OG: "Hi, I'm looking for somebody to help me set the computer in my [newer car]."
Me: "Okay, set what? What are you trying to do?"
OG: "Forget it! You can't help me!"
He then proceeds to walk off angrily towards his truck. In an attempt to be somewhat helpful, I call after him (in case he missed the signage and general clues of where he was, as they usually do), "I'm in the service department, I can answer your question."
He gives me the typical grumpy-old-man arm flail that usually means "forget it, you're just a woman and I'm done here," and drives away.
These interactions are not rare by any means as Farmer John simply must know more about cars than me, but that one was definitely the fastest I've pissed anybody off.
I never even had time to put down my book.