Why in India, at least in Chennai, do walkers do their best not to make eye contact? Ok, they may be complete strangers but one walker will either acknowledge another with a cold stare or furtive glances, or simply by turning away his or her face to avoid any expression.
If someone does decide to overlook these cold-shoulder techniques and smiles at another co-walker, he or she is usually greeted with suspicion -- either a suspicious look or a tentative half-smile which says: SHOULD I be smiling back at you?
I usually appraise a co-walker in the far distance and screw up my eyes in concentration to see if he or she is recognisable. If so, then I quickly think of how to go about saying hi and figure out whether I really want to stop and talk or just pretend to see them in the last moment and quickly say hi, how are you and bye. If I don't know them, so much the better. As I get closer I 'check' him or her out and then decide if I fel like giving him or her more than the one furtive glance (Thiruttu muzhi it is called in Tamil).
'When in Rome...' syndrome, i call it. Don't want to be known as the only whacko who smiles at everyone in sight.
Of course, I need to clarify at this point that I do not really qualify as a 'walker' -- two days does not cut it. But having gone for walks erratically and otherwise for oh so many years, I have observed enough walkers to know better than to smile at co-walkers I don't know.
Mostly cos I hate it when my smile is not returned!