In my experience, this depends on the context. Everywhere I've lived the only time strangers try to talk to me is to either a) ask for directions (1%) or b) beg for money (99%).
I see people in these comments suggesting we should just say no thanks I don't want to chat -- I'd have to repeat that a dozen times a day. It's exhausting and I don't gain anything from it. I figure these folks must live in totally different locations.
> I came from a small village where it is normal to greet people and maybe chat, even if you don't know them.
Yeah, I could see that. If my village/city wasn't plagued by petition beggars or money beggars or merchant beggars I'd probably be more interested in engaging.