Sure, this dive has a full menu of pub-style food like fish & chips and rib tips, but what R.F. O'Sullivan truly specializes in is juicy, portion-defying burgers. Each half-pound burger takes upwards of 20 minutes to prep and cook, but your patience will be rewarded. There are a dizzying amount of combos, from the blue cheese Black & Blue (with French fries and onion rings) to the avocado-and-Swiss Cape Codder. Wash it all down with a whipped cream-topped root beer float.