You ever buy chips in the store? Potato chips or tortilla chips or the like? You've probably seen how they're half full of air. The manufacturers do this to make it look like theirs are bigger, and you're getting more chips.

Wouldn't you be impressed if you picked up a bag and it was full? Aren't most of us more impressed by value than size? Wouldn't it seem so much heavier, and therefore a better deal?