I was in Maplins a while ago and was waiting to be served, the guy on the till said "..be with you in a minute, the till roll's ***ed".
I wasn't dressed particularly smartly that day and presumed he thought he could talk to me like that based on my appearance.
So I answered "The till roll's WHAT?"
"..er, broken" he replied.
Now I'm no prude and am totally into swear words but it was that presumption that irritated me.
No one should presume ANYTHING about a person's right to basic respect IMO whether they be dressed smartly or not. It's all about how we behave, not how we present ourselves.
I treat people the same ALWAYS, whether they be suited and booted and clean shaven, homeless and scruffy, dressed in black leather with purple hair and studs etc etc. I have many more stories of people being "not as one might expect" despite their appearance.
It works both ways for me: I can be just as cocky and familiar* with a be-suited MP, lawyer or celeb (and have done many times) as I would with anyone else.
It's a cliché but never a more true word was spoken afaic than "you can't judge a book by the cover".
(*within reason)