I moved from NYC to the rural reaches of upstate New York when I was 11. My family and folks I hung out had a mixed of "Lunged Idland", Brooklyn and Irish accents. Nobody had any idea what I was saying for several months after moving, with good reason.

The accent still pops out once in awhile, usually when I'm tired or agitated. Some folks find it grating or aggressive. I just tell them to screw off.