@Momosuke I think it comes from that European tradition of kissing each other's cheek as a form of greeting. For example look up Faire la Bise.
I think its also the fact that Europeans and American are normally more open and expressive with their feelings where Japanese prefer more reserved actions like how a Yamamoto Nadeshiko acts.
A counter example is how most westerners think all Japanese are perverts or more comfortable with sex but in reality its just that they laxer rules about sexual content in media than the more puritanically driven US censors.