I really don't feel that there is an overarching white culture in the United States circa-2009. Even Stuff White People Like is really only accurate for a small subset of white people. Things that lots of people consider to be super-white aren't even like that anymore. Golf, tennis, Star Trek, libertarianism. All of these activities have minorities in positions of eminence nowadays.
So tell me, what culture is it that immigrants have to assimilate into? If there's no white American culture then what is the origin of the phrases "Americanized" or "Westernized" and what the hell are radical Muslims waging Jihad against? Why is America's number one export it's culture (hence the Coke and Pepsi reference), but evidently there is no culture to export?
I'm not saying that non-whites haven't contributed to American culture, but referring the origins of many aspects of American culture. Thankfully they're being diluted which is why salsa is outselling ketchup and Chinese carryouts are in even the most lilly white areas.
Relationships have normal ebbs and flows. They do not automatically get better and better when the participants learn more and more about each other. Instead, the participants have to work through the tensions of the relationship (the dialectic) while they learn and group themselves and a parties in a relationships. At times the relationships is very open and sharing. Other time, one or both parties to the relationship need their space, or have other concerns, and the relationship is less open. The theory posits that these cycles occur throughout the life of the relationship as the persons try to balance their needs for privacy and open relationship. Interpersonal Communication Theories and Concepts Social Penetration Theory 1 Social Penetration Theory 2 Social Penetration Theory 3