Are Londoners really as rude as people would have you believe?

Having visited London several times and travelled extensively on the tubes and buses during both rush hours and at other times of the day, I can honestly say that I have never encountered the rude and unfriendly side of Londoners which we constantly told of. I live in the North of Scotland, about 500 miles from London where people are percieved as being friendly and welcoming. Yes, your average Londer isn't quite as warm and friendly as someone from my patch of the woods but by no means would I call them rude whatsoever. Most of them seemed pretty decent and polite to me, something which completely contradicts the stereotypical image of rude Londoners which people in the North take pride in telling other people of. Is it just me that doesn't think Lononers are that rude or am I mistaken? Thanks in advance for your answers :)