Gottagettolondon: You're absolutely right! Lack of small talk is one of my favourite things about the French.
AnneR: I doubt we will ever agree on this, but I will attempt to explain how I feel. First, on the subject of small talk topics--I agree that "how about the weather" and "did you have a nice weekend" are harmless space-fillers, and can be answered in a word or two. I guess even "where are you from" wouldn't bother me too much if I could just say "the US" and have that be the end of it. But the questions that follow "what part of the US" "why did you come here" "how are you adjusting" "do you like it here" etc go far beyond chit chat and are actually kind of personal and can have complicated answers. For example, I was born in New Mexico, grew up in Wisconsin but haven't lived there for ten years, lived in New York, lived in California. My dad lives in WI, my mom in CA. CA is my favourite state and where I felt the most at home, but I only lived there three years. So where am I from? If I say CA, then they ask why on earth I would want to leave, and if I say WI then they don't have a clue where that is and I have to explain. The truth is, I have strong ties to both places, but I really don't want to get into that much detail with strangers. The weather and the weekend aren't nearly so fraught.
Second, about the "thinking before you ask" issue. Try looking at it this way: people think they are being friendly by asking questions, and that they are "just curious" so it's OK. But there are lots of things people might be curious about that aren't appropriate for discussion ("What IS that thing growing out of your head? Just curious." I know, extreme example, but still). And as to being friendly, what is that, really? If you ask a question of someone without wondering whether it's an obvious question or one they're likely to have been asked twenty times already that day, then you're putting them in the position of either replying with their honest feelings and possibly being considered rude, or of repeating the same polite exchange for the twenty-first time. So it might actually be friendlier not to ask, or to bring the subject around in a different way. It doesn't seem like it could hurt anything just to wonder how a question might make someone feel before asking it.
AyouBob: If you really want to know the best way to start a conversation with me in a shop, then I have to refer you to the questions I listed in the post of mine that you quoted in yours. If you jumped right in with "Where are you from?" then I would just fob you off with the quickest answer I could and make my escape, because I wouldn't think that a conversation begun in such a manner could lead to anything interesting. But if you came up to me and said "So, do you like ice cream?" or "I always wanted to be an astronaut. What did YOU want to be when you were a kid?" then you would catch my attention and I would think that you were unconventional and likely to have more things to say that I would want to hear. I would laugh and reply and probably ask you something in return. That's just my minority opinion, though. Seems like you'd be safe enough with the ol' "Where you from" with most people.