You probably emember the story of the three little pigs. To reprise the Disney cartoon version, they started off as three young porkers with ambitions to construct their very own personal residences.
Presumably, as a rational porcus economicus, each wanted to maximize his utilities. Each wanted his house to give him privacy, shelter, comfort and protection. They each wanted efficiency—at the lowest possible price point but consistent with their personal goals and tastes. For example, one little pig, the environmentalist, built his house of straw (thus employing a common, renewable resource while efficiently utilizing carbon and minimizing his heat bills). Another, the cheapskate, used mere twigs as his primary construction material. Twigs were available off-market. The material was cheap and easy, but it was also vulnerable to attack and deterioration.