Friendly Smile

When I landed in U.S, an American guy smiled at me and said "Hi". I was sure that I have never met him in the past and didn't even remember seeing him before. After spending many days in U.S, I realised people here are very friendly. Americans in general pass a genuine smile and convey a hi to any alien. So if you hear some American saying "hi" don't ever think about "who that person is", just say a "hi" back and keep moving.