When a person who has suffered a head injury that resulted in memory loss sees a face that actually looks familiar some of us overreact. We may seem like we are harassing but it isn't that. Its just so amazing to see a face we recognize that it is nearly overwhelming. We cling desperately to that familiarity hoping for confirmation of it. You may have been someone we used to pass on the street or shop at the same store and never actually met but that is enough to give us some sense that we actually did exist here, that we are not strangers to this place... that we are not completely gone. So if someone asks if they know you don't completely write them off as a pervert or nutjob. They may be someone who suffered a head injury seeking acknowledgement of their existence or fragments of their lost past.