The American Dream, to me, signifies both the philosophy of individualism and the attitude of "I Can". To the extent those two aspects existed in our culture, people prospered. You have the ability to pursue your goals, whether they be concerning family, money, friends, etc.
What bothers me is how we've moved away from that and to a culture of envy, hatred, and entitlement. That is what is wrong with America today. People hate the rich for being rich, people think they have a right to heathcare and welfare, and personal responsibility is all but non-existant today.