Anyone have a link so I can see it?
Despite what people think, accents aren't exactly easy to do, and a lot of actors "overdo" the accent, esp. if it's Southern, Cajun or British. I wince whenever I hear someone trying to pass themselves off as any of 'em and it's so obvious they're NOT! ("I GAR-RUNT-TEE!"). Or worse, start off with one and drop it midway through the movie (Kevin Costner, anyone?

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Though I've heard British actors do a passable American accent, and Americans do a passable British one. Either way, it's harder than it looks.
When Malcolm did the "Keep your shirt on, Loo-tenant" it's obvious he's being sarcastic and not really wanting to duplicate at true Southern accent. I heard DK once with a Midwestern "neutral" accent and it was OK.
Personally, I love the Cajun accent. The previous quarterback of the Carolina Panthers football team came from breaux Bridge, LA and his accent was just charming. Not overly thick, but enough to know where he was from.