[pafje]

About people being instantly friendly and then ignoring you later on, I've heard the exact same thing from french students in America. In France, people will generally be very polite upfront but not overly friendly. Friendship has to be build over time (nothing is valued more than decade-long friendships, it is the subject of many french movies). I think many other (western) European cultures are similar in that respect, so it might be an American thing (in the spirit "everything has to happen now or never").