I can't even begin to explain the exceptionally amazing hospitality that I have experienced with the Thai people.
A smile goes a long way.... from opening up a conversation and gaining the inside scoop and tips to getting free treatment at the doctor's office. I have gained and learned so much from speaking to others, the best way I can literally. But the interactions with the people, initiated by a smile, are simply priceless.
If you are exposed to someone who seems standoff-ish or unpleasant, chances are, they have been having a bad day. So give a smile and help to brighten up their day=) It comes back ten-folds.