material desire

I suppose I have less material desire than ordinary people. On the other hand, my co-worker has more material desire than ordinary people. He have gotten his own car and house ever. And, a wife and a son. It apparently seems almost perfect life. Also he said he is pleased with his present life. But now that he got much, he wanted other new one, he said. As I asked to him, "What more do you want?", he answered, "Much bigger my home." I don't know his thought but I thought I might understand such feeling when I got my home, car, husband or son.