This is not possible to see like if you follow the economic phrase too that says human wants are insatiable. So it is a human attribute or character to want things and if they want many things they keep looking for the satisfaction and the satisfaction is get that thing. That phrase of yours of "what you don't have, you don't need" is not proper because you only can think you don't need it because that you don't have it, I think I put it in another way  . You know everyone like to have good life but we need caution and moderate.