For years, Americans enjoyed the "wealth effect," the sense that their assets were gaining value rapidly enough that they didn't have to save much. This perception of ever-expanding prosperity gave them freedom to spend lavishly and enjoy life. The effect was a function of feeling wealthy as well as being wealthy.
Well, that was then. Since 2008, Americans have endured a de-wealthing, so to speak, as the value of their assets plummeted and many jobs disappeared. Those who can are saving like crazy.