Since I don't live in the U.S. full time, but only come over for the summer for Anime Expo and the San Diego Comicon, I sometimes notice things in the U.S. that I might not pick up on if I were here year-round. When prices of the things I buy go up or down I generally notice it, and when some new slang word becomes popular suddenly -- this trip I've visited several restaurants in San Diego where the staff calls me "boss," e.g. "sure boss, that'll be $9.50, boss" -- it tends to stand out to me. Whenever I go to the supermarket, I know I'm likely to see several random new variations on familiar products, like Canada Dry Green Tea Ginger Ale, or Cocoa Puffs Brownie Crunch, or the new Peanut Butter Cheerios.
I always find strange new foods when I visit the U.S.