Globalization and Root Beer

http://www.americansweets.co.uk/index.asp

As part of my planning for Thanksgiving dinner, I just did a Google search for french fried onions, and found this retailer. They sell American groceries in the UK. My American friends back home will look at the website and laugh at the prices (£4.50 for a 2-L bottle of Root Beer???), but my American friends in the UK will look at the website and actually consider paying the exhorbitant prices for things they've been missing (a root beer float sounds pretty good in the land of tea...). Libby's canned pumpkin seems to be a big seller (I brought a big can back with me this time, worth £4.30 on this website, along with jellied cranberry sauce that goes for £2.45!).

This doesn't even touch on the wide range of American companies & products we have access to in our every day lives in the UK. Everyone always mentions McDonald's taking over the world, but we've got other companies here, too:
Starbucks
KFC
Burger King
Pizza Hut
Domino's
T.G.I. Friday's
Costco
Staples
North Face
Ralph Lauren
Gap
D.K.N.Y
American Apparel

and I'm sure many others that I haven't remembered...

How do we participate in 'culture learning' when globalization has made it so easy to access a taste of home? If globalization means Americanization, as some scholars have argued, then why do Americans still feel culture shock when they go abroad?