Thing is talk to them one to one and don't mention football and, hideous accent apart, they aren't too bad. Get them on about football, or if there's a pack of them and the change in personality is astounding.
This in bucket loads!
I know a load of mackems, in fact I have a canny few mackem friends and they're all great people but my good god, once you get onto football or in particular, Newcastle United the absolute shite that falls out of their gobs is beyond belief at times. Bitter and obsessed is an understatement.