There are many ways to say hello in the United States. Depending on how well you know the person, it may just be a head nod, a handshake, and sometimes even a hug. If the relation is familial, the greeting can even be a kiss, but this is only to those you are extremely closely related to. In other words, I never greet the people in our church in the States with a kiss. This would be at best “very strange”, and at worst worthy of a strong confrontation. That is the way things are in the States. On the other hand, there are many times when a person walks into a room of people, and instead of shaking everyone’s hand and greeting them, the person just gives a simple head nod and says “Hello”. This is perfectly acceptable in some contexts.
In Argentina, things are totally different. It would be considered rude to give a small head nod to people. I have watched someone come in late to an event, and to greet every single person who is in the room individually. This is strange to me, but then, it is not strange at all, I am the strange one. The adjustment must be made to greet everyone! For example, when you walk in to a church, you greet every single person. The way we greet people here differs depending on how well you know the person just like in the States. If it is your first time meeting them, and it is a man meeting another man, a simple hand shake will suffice (along with a kind word). If a man is meeting a woman, a kiss on the cheek is customary. When I use “kiss on the cheek”, I mean cheek to cheek and making a kissing sound. The same goes with a woman meeting a woman, a cheek to cheek kiss. When two men who are friends greet each other, they do so with a cheek to cheek kiss. If they are really close, it is a cheek to cheek kiss along with a strong hug. This is how we greet. There is obviously nothing inappropriate going on in these greetings, it is just the customs. This adjustment was made almost immediately for us. There are tricky times when you don’t know if you are supposed to greet with a kiss or not (an Argentine friend tells me even they have those uncomfortable times when they are not sure how to greet someone), but most of the time I just go in for the cheek to cheek kiss. My kids have all adjusted to this as well. It is now just a part of our lives.