A friend asked me how to strike up conversations with strangers. I told her what I’ve said many times. Three things make it easier:
1. Recognition. If you recognize someone (and presumably they recognize you) it will be easier to start a conversation.
2. Real question. If you have a real question — a question to which you really want the answer — it will be easier to start a conversation.
3. Shared suffering. If the two of you (you and the person you wish to speak to) have suffered together — bad weather, stuck in a long line — it will be easier to start a conversation. Living in Beijing and not speaking Chinese is another example of what I mean by “suffering”; another name for this factor could be shared predicament.
Those are the main factors that matter. In everyday life, they vary a lot. Another factor is minor:
4. Forced proximity. If you are forced to be near each other — in an elevator, say — it will be easier to start a conversation.
If none of these factors are true, it will be very hard to start a conversation. If one is true, it will be somewhat hard. If two are true it will be easy. If three are true it will be inevitable.
In my experience, local culture makes a small difference, somewhere between zero to one on this scale. Most places are zero. A place where people are really friendly would be worth one.