Here's a fact about life: things change.

Now that is hardly a profound observation, but it is a significant shift in thinking that for many of us can only be gained by living a while.

Think back to when you were a child living with your parents. Whatever the circumstances of your home life, you likely had a sense that how things were in your family was more or less how things would always be there. It is a natural mark of immaturity to think that things won't change. In high schools, for example, kids who are not in the cliques often believe they are destined to be outsiders forever. When romantic relationships break up, kids sometimes see that as portending a lifetime of unhappiness, with nothing ever changing or improving for them.

At the extreme end of that shortsighted outlook is th…