Today, I stopped at a 7-Eleven for a soda. Previously, I have purchased the 32-oz. Big Gulp. However, I realized that for less than 33% more, I could get 100% more soda by purchasing the Double Big Gulp. This drink is outrageous. It requires a special extra-long straw. A random man who witnessed me sipping it pronounced "That is too big for you." And yet because the marginal cost of the additional 32 ounces was minimal, I bought (and drank) the whole damn thing.
I have also been to Frozen Yo, where they charge by weight for whatever mix of yogurt(s) and topping(s) you desire. The containers are, in fact, large. But because you pay only for what you want, and larger sizes are not artificially cheaper, I was perfectly capable of getting just enough birthday-cake-flavored froyo to satisfy my jones without feeling embittered that I had to shell out some fixed amount for a portion size not based upon my appetite. Anyone disparaging this utterly logical method of dispensing yogurty goodness is 1) un-American and 2) a tool of the Vast Fattening Conspiracy.