Hm. I stared and smiled at a a dad with little daughter in the subway. They were a cute pair, it is rare to see a dad so well matched to a child in public. The daughter was more daring than her dad, while he ignored me being charmed the girl did wave me goodbye when they left. - When I checked my tired face in a mirror on the x-mas market I found a few spots that needed repairs and I bound my hair as a pony tail. While I worked a bit on my appearance which took less than a minute a young lad focused on me and smiled all the way as he thought it would be unseen by me. It was a smile that expressed a bit of "I like what I see" combined with a bit of "typical girl business to look after the appearance, we boys do not need that". - None of these example were of the creepy or maniac sort I think. In a friendly society people smile at each other more often. In societies with much pressure smiles are more rare since they could be interpreted as signs of weaknesses or personal interest, as an offer. There are many people it seems who do not know the difference between friendly smiles and inviting smiles.