Why do some failures inspire breakthroughs and others breakdowns?

Most new products fail. So do most businesses. And most of us, if we are honest, have experienced a major setback in our personal or professional lives. Exploring her own experiences of failure - losing her job and sending CVs into a void, clinging to a relationship that was clearly not working, Megan McArdle shows how to recognize when you're in a rut and how to bounce back successfully.