I f***in beg to f***in differ. Irish people do not speak like that any more than the Scots say "och, aye the noo". wtf do you find saying f*** funny?
The interesting thing is that only Mrs Brown uses the "F" word on the show....you never hear it spoken by any other character. I think the reasoning behind this is that spoken by one of the younger characters like Buster or Maria, it would indeed sound coarse and vulgar, but the basic comic premise of the show is to have the unlikeliest of characters, an elderly grandmother and matriarch swearing like a trooper.