Depth of friendship

I kind feel big differences about friendship between Americans and Japanese/other nationalities.
I always feel difficulties getting friendship with Americans. One of my friends told me, "It's just language barrier".Well, I had a chance to talk to British person about this .She had the same idea about having friendship with americans even she speaks English.
I think America is the country which people come and go in short time. So I feel people are kind cool about having relationship , it could be any kind of relationship, but it is kinda cold. It really depends but I don't know. I just feel comfortable with latin people. They are so warm and friendly.I am not saying americans are not friendly. Actually they are friendly. I feel like sorta , hmmm like distance or huge , think wall between them and me? something like that. well maybe I am just bitching or saomething. I don't know. It is just hard.