What you need are things necessary for survival, such as physiological needs. What you want might not be necessary for you to live, but those are the things you want to have in order to be happier. Humans have unlimited wants. For example, if you have a house, a dog, a regular car- you might want an airplane or a bigger house or a bigger car. But humans will never have all their wants met- because everyone will just keep wanting more and more. Even the richest people still want something more.