Unpredictable things happen to us all the time. As part of our annual You 2.0 series on personal growth and reinvention, we revisit two of our favorite stories of loss and the change it brings.

We don't always behave the way economic models say we will. We don't save enough for retirement. We give money to charity. This week, why we act in ways that go against our "rational" self-interest.

The turn of the year is a time when we set the old aside and welcomed the new into our lives. When one chapter ends, another begins.