Downsizing...why do people have a hard time understanding?

Selling a larger house for a smaller one, getting rid of excess ';stuff';, getting a car that is more fuel effecient, etc. We have decided to downsize our house and clear out clutter and save money. Our lives will be simpler, and hopefully less stressful. We are buying a new build and the friends and family that have gone to see the model all ask the same question ';Why didn't you get the bigger one? It's got so much more space!'; Ummmm...hello!? We don't need it, don't want it and aren't going to get it. Why do people not understand the economics side of downsizing? Just because we can doesn't mean we need to go bigger. Anyone have any good resources I can point them to to help them ';get it';?