Imitating accents

A very old thread was recently added to, so it popped up to the top. It had evolved  into the success (or failure!) of American actors immitating UK accents and perhaps vice versa. But how do Brits from London do imitating the very distinct Yorkshire accent? Or how well does a Scot do immitating someone from the Liverpool?

I ask because I'm often appalled how Americans try to imitate a Southern American accent, and do it horribly, or fail completely at a very distinct regional accent like Maine. I lived there for 15 years and I can't do a credible Maine accent - although I sure can tell when it's being done badly. It seems clear to me that you don't have to try to cross an ocean to do an accent badly.

What do our UK cousins have to say? Can you sound like a native from any part of the UK? I expect you have the same trouble as someone from Chicago trying to sound like he's from Texas!

Well, I can do good Southern, because my father is from there, but I'm hopeless at New England, even after living there. And I have no desire at all to replicate the local Philadelphian accent. It's just amazing how a hundred miles can completely change the way people speak, isn't it?

Hmm, I think the purpose of imitating an accent is to entertain, isn't it? So the accents don't have to be perfect, they just need to be very close to the original ones.
If you want to do a perfect accent... heh, that's practically impossible. Let's suppose people from Houston TX have a particular accent. Maybe it's not difficult to sound Texan to New Yorkers. But how about sounding like you are from Houston to people from other parts of Texas? That's more difficult, probably very difficult. And how about triking people from Houston, making them think you are really from Houston? That's extremelly difficult. Maybe you can, but if you just say a short sentence, as Jim said. Not in a long conversation... I think that would be impossible.