Just that really, it winds me up.
People say to me often "Oooh, you're proper Welshy aren't you?" In the most really over exaggerated Welsh accent. I just say "Yes, it's because I'm Welsh, would that be hard to work out?" Then they get the hump.
I've seen it when people meet someone from the North East and star with all the Way Aye Man shit.
Just why do people do it? It just makes them look and sound so stupid, like they'd never expect to meet someone from outside of their town, ever.