There is no reason for such behavior anywhere in the world. But the sad reality is, there are people everywhere who behave unreasonably and in uncivilized manner. One could hope that slowly there would be enough education and progress that eventually, everyone will in an appropriate manner. I live in Georgia, US. I can assure you there are plenty of nutcases here. What you just described happens with me yesterday as I was driving with my little son in the car seat. The driver started chasing me and I had to run away as fast as I could without having to worry about speeding. Additionally, Georgia is a gun friendly state so almost everyone has a gun in the car. I am suppose to be living in one of the most civilized nation, but guess what. Most ridiculous things happen over here as well. And to tell you the truth, most of my "American" friends are ashamed of these unruly characters. But again, you will find them everywhere. The trick is to stay out of their way as much as possible and not allow them to ruin your day..