I live in an area with a moderate amount of foot traffic. Every now and then I'll get a "Hi" from a stranger. In fact I've had people get offended by my lack of a response. I think that something that us shy people/introverts need to better understand, is that interaction between strangers is normal. We need to get past these mental images of people getting offended over simple communication. Stop projecting personal insecurities onto everyone else and let that inner extrovert see the light of day.