You've received wonderful suggestions but I cannot resist adding mine!
Mexico: Margarita!
Norway: Cheese plate from the bakery
China: Bubble Q Tea (it's a cold, fruit flavored milk based drink)
Outpost area: Frozen strawberry smoothie style confection
Germany: Like so many others, a pretzel, or almost anything from their sweet shop
Italy: any granita from the outdoor stand
USA: hot french fries here are the best!
Japan: Tempura in the Matsunoma Lounge (two butterflied shrimp, green bean, sweet potato slice, carrot slice-a wonderful break from the hectic park!) and a frozen Mikan drink
Morocco: Frozen tangerine from the outdoor kiosk, or any pastry from that kiosk or the one inside the cafe!
France: Cheese plate from the bakery
UK: Cheese plate in the Rose and Crown
Canada: Popcorn! This outdoor cart sells the best!
Obviously, I like cheese. Have fun!