well, you are being genuine, you just don't want them to approach you. Would you feel the same if it was a cute chick?
would you be interested then? random acts of kindness such as a smile are usually reciprocated with the same. Unless you are winking at them, they usually dont approach. However if you find that a particularly strange one does, simply excuse yourself, and run
( or at least walk away)
Smiles and laughter are infectious and should be used often.If you choose not to, then you become the sad, not smiling, lonely person that you are describing.
