I don't know, I try to smile if I make eye contact with someone and that's about it. Though occasionally since the person knows I'm not some derranged psycopath waiting for the right moment to pounce on them and quench my cravings for human flesh now since I gave such a polite, dainty smile it'll make them more comfortable to open conversation. Which usually doesn't bother me unless I'm in a helluva bad mood, but even then I try not to bring people into my problems when they're perfectly innocent.
Then again I'm always up for some awesome elevator music. 'Summer Samba' anyone?