I probably come here once every time I'm in Vegas because there's always a need to stock up on drinks/snacks/ramen or pick up some fresh kimchi or get some bulgogi in the food court.
Greenland always has plenty of people because it's a nice oriental market (mainly Korean).
My favorite things are the pastries from the bakery, the food court, sac-sac grape drinks, mandoo, kimchi, and everything else in the place.