Can't say I have ever had any problems with rudeness in general in either Inverness or Edinburgh though maybe the kind of places I go to/people I frequent with. Actually had way more bad experiences when I worked in glasgow (though not really rudeness issues, just idiots trying to give you a random kicking/stabbing). London was the worst but again you can always find lots of ameniable people. I think though in general cities where there is less of a "local" crowd and much more people in transit/tourists/rushing business folks then it will be a bit colder and less intimate. Aberdeen can be a bit hit or miss but since I moved here from the Dublin area (which can be very rude/cold at times) most folks have been fine but the chav numbers seem to have multiplied hugely in the 4 years I have been here.
Some of the small villages in Scotland can be a total nightmare though and I have had a lot of pub moments like a scene from American Werewolf in London. I find a lot that people can have very "coloured" opinions of Scottish cities dependant on upbring/place of birth/friends etc, what they might tolerate in one they would rant about in another, having a mum from Edinburgh, a dad from Glasgow and split polarised family in both cities can be an eye opener, especially at weddings and funerals!
Football to seems to be a major definer for many and my cousin in Bellshill was very vocal about me going to live with the "sheepy scum" and he wasn't joking either.