People will always try to figure you out. But with the German stare this communication is enhanced, you get feedback on their feelings for you and you can respond to that with your attitude. In other cultures, they make a judgement and there is nothing more to be done, they close down. In Germany this channel of communication and feedback stays open and works, in my experience, collectively. Once you develop an attitude that works that stops the ugly stares in the grocery, then stares become less threatening in general, collectively. It does seem to be a kind of a super-organism behavior that isn't very well understood, which is why I find it fascinating.