I've never been to a Which Which, but was pleasantly surprised with the operation!
Think of Potbelly, but a little more customization. You grab a bag from the wall and check everything you want on your sandy. Do you want red onions, mustard, swiss cheese? Just make a check and don't forget to add your name! Bring your filled out bag to the cashier and pay for your order. In no time your order is up and you'll be enjoying your personalized sandy!