One of the key considerations is how quickly you can move customers in and out. Ever work at a busy diner? One of the little tricks of the trade is to make sur

One of the key considerations is how quickly you can move customers in and out. Ever work at a busy diner? One of the little tricks of the trade is to make sure the coffee's not too hot. You want the customers to suck it down immediately, not sit around an extra 3 minutes waiting for it to cool. It's probably more efficient and streamlined to give customers a drink rather than having them mill about at the fountain, and it's definitely more efficient to clear out loiterers who are hanging around and sipping free do-it-yourself refills.