I have had the pleasure of driving in many parts of the world. Being fairly observant and having a tendency to theorize about everything, I have come to form a general theory about driving habits as well.
You see, each place has a set of driving norms, a grammar or a dialect of driving, if you will. In Marseille, France, for instance, if you switch on your turn signal on a multilane street, people will immediately let you in. It’s not because they are polite and considerate drivers (quite the contrary, in fact), but a turn signal indicates the drivers’ intention to change lanes, not a request to let them. They are not seeking permission; they are merely letting you know. You’d better let them in unless you want a collision. In Geneva (Switzerland), on the other hand, the turn signal is really a request, which is usually denied.