There are times in life when the challenges we face feel insurmountable. Authors succumb to writer's block. Athletes and artists hit a plateau. People of a certain age fall into a midlife crisis. These are all different ways of saying: I'm stuck. This week, in the kickoff to our annual You 2.0 series, psychologist Adam Alter shares his research on why we all get stuck at various points in our lives, and how to break free.