The old man explained to the manager that he has found happiness through living simply and being content with what he has, rather than constantly wanting more. While the manager thought he must be unhappy living in a small house and owning just one truck, the farmer was happy because his simple possessions fulfilled his needs. The farmer said that true happiness comes from having a happy mind, not money or possessions, and that being content with what you have, rather than constantly wanting more, allows one to find happiness.