Like many stereotypes, there may be some elements of accuracy, but for the most part, it's an unearned reputation.
I've visited France several times and I have no recollection of encountering the infamous "rude waiter". If someone asked me where I met the most rude people in all my travels, I would have to say it was probably the UK. But, I lived there for a couple of years, on top of several other visits. So, it was probably more a function of longer exposure than any real difference in politeness.
There are rude people everywhere. I've travelled quite a bit in the US and I never encountered more rudeness there, than I have anywhere in Canada. I sincerely believe that more polite you are, the less rudeness you will encounter.