Chain: Dunkin' Donuts
Introduced: 1972 

Dunkin' Donuts Munchkins are addictive, no doubt about it. You start off eating two or three small donuts, and before you know it, the entire box is gone, along with a little bit of your dignity. The Munchkin addicts of the world need their own help group—Munchkins Anonymous.

Dunkin' Donuts sells 1.9 billion donuts and Munchkins every year, which goes to show that people love their unconventionally-shaped baked goods.