I remember when we returned from holiday wondering if my wife was pregnant.
We drove to the local testing place, and our car died on the way.
A car pulled up, and four seriously salty looking guys got out and advanced towards us, looking really menacing.
They could not have been more helpful - they pushed our car to a safe place, jump started it, and when they found out where we were going, they wished us every good wish for the future.
As you say, never judge a book ...
Actually, I experience that regularly when i attend extreme metal gigs as a music writer.
I look like a retired bank manager, I have a Number One, glasses, and I'm sixty-six - I look like someone's grandad who has turned up early to pick up his grandson and friends.
But the chances are, I have been discussing the finer points of the genre backstage with the band before the show started, and will be joining them again after for a curry and a wind-down.