I have encountered this too in numerous ways with food. It's homesickness, plain and simple. And once you are home, whether or not you call America home anymore, the craving sort of disappears. Or if you do sate it it's never as good as you hoped. Well, usually, I do still miss rootbeer and Nilla wafers and will indulge in them when I get the chance! I remember your Little Debbie moment well!