Never used to be this way, but McChicken Sandwich. Back on the oval seeded buns, with the thicker, juicier chicken patty, it was well worth it. Nowadays, it is only marginally bigger than the Mayo Chicken (£1) but almost 3x price. For me, it's:
McChicken Sandwich<Chicken Mayo<KFC Tower<McChicken Legend<BK Tendercrisp<KFC Fillet<KFC Zinger.
Worst example of FAST FOOD DESSERTS, NOT ICE CREAM?