Something that always shocked me in my travels to USA is how much people smile at you. The most weird thing is that it doesn't seem that fake, it seems complete

Something that always shocked me in my travels to USA is how much people smile at you. The most weird thing is that it doesn't seem that fake, it seems complete strangers are just not afraid of you and happy to see you. Contrast it with Brazil, unlike USA people don't smile at you in the streets there, but if they know you they can't stop laughing. Brazilians parties are non-stop full-volume laughing. It's maddening!