Looking strangers in the eye is something I have always had big problems with (although I am better at it nowadays), and to SMILE at them as well...! If I did that, especially to another guy, I'd expect him to think I was hitting on him and would be afraid of going home with a black eye for my troubles.

It is easier, of course, if the stranger speaks to me first, then I am fine with it, but not otherwise. I was not brought up to smile at strange men!!!!! ;);)