Galleria is a large Korean supermarket that sells mostly Korean and Japanese groceries. It also houses a cafeteria, bakery, health product counter, and some boutiques. It's a great place to go for one-stop shopping.
The cafeteria is a bit hit and miss. Some good menu items like the pork bone soup (flavorful and tender pork), and then some outright terrible ones like the Korean traditional noodles (bland noodles in a bland kimchi broth). Service is generally good, though brusque at times. Solid experience, all in all.
Wi-Fi is also hit and miss, but hey, it's free!