If you listen closely to giggles, guffaws, and polite chuckles, you can discern a huge amount of information about people and their relationships with each other. This week, we talk with neuroscientist Sophie Scott about the many shades of laughter, from cackles of delight among close friends to the "canned" mirth of TV laugh tracks.

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.