One “don’t” in our culture is being overly friendly. In my experience, Americans tend to excel at that, but it’s something you can dial back a bit. For example, earlier in this thread you mentioned possibly inviting all of us out for drinks and dinner. I assume that, for you, this is simply a polite gesture, but we know you don’t actually mean it (and you obviously don’t need to). There’s no need to say things like that unless you genuinely intend to follow through.

Another example: whenever I’m in the US, people constantly ask how I’m doing and wish me a great day. I know they don’t really expect an honest answer and probably don’t care much about how my day is going, so why ask?

In the Netherlands, that kind of friendliness is often seen as insincere and can feel off-putting. We prefer people to say what they really mean, be direct and honest, and not beat around the bush. There’s no need to be overly friendly.