This concept applies to daily life because we most prize things that we have the least of. A great example of this is food. Imagine that you are really, really hungry and you go to a sandwich shop. You buy one sandwich and eat it. You really needed that one and so it had a great deal of utility for you. It made you stop feeling all sick and weak from hunger. Now you buy a second one. It's good and you enjoy it, but it didn't do as much for you because you didn't need it as badly. Now think about a third sandwich. You're not going to get much utility out of that one because now you're just stuffing yourself. The more you have of something, the less valuable it is to get one more of that.