Jewish law describes the Succah as a temporary dwelling. Leaving our permanent houses with solid walls and roofs to live in a flimsy booth with a roof of branches is a dramatic statement that the material world is not all that life is about. By living in the Succah we are declaring that the entire physical world is really temporary, and that the only things we possess forever are the soul and its spiritual accomplishments.
It was certainly within God’s power to build five-star hotels and spas for the Jews in the Sinai desert. Why then did He put them in thatched huts? Because He wanted them, and us, to understand that there is permanence to the physical world. That focusing all aspirations and hopes on material attainments — a house, a car, another house, another car — is pointless. By living in the Succah we are bringing this message home to ourselves as an understanding that will impact our lives.