If there's something that become endangered in the last two generations, it's the idea of sacrifice. We went from being the most respected and feared country in the world, to being the laughingstock of even third-world countries. I think this came about, largely, because of the elimination of sacrifice in America today.
Sacrifice /ˈsakrəˌfīs/- An act of giving up something valued for the sake of something else regarded as more important or worthy.
Think about it. How can you sacrifice for something "regarded as more important or worthy" when the most important thing in your life is your own comfort? When we value comfort, laziness, and entertainment above all else, we turn sacrifice into a mockery. There is no reason to give anything up.
By definition, there must be something more important and worthy to sacrifice for. We must intentionally choose what things are noble and worth pursuing. Otherwise, we fall into the default state of "whatever." People who have changed the world did it because they had a perspective for something bigger, something greater.