The Power of Make-Believe

What place does an active imagination have in adult life?
The current issue of Time magazine has an article about how imaginary friends can help kids develop healthy relationships with others later in life. They learn coping and communication skills.
One mother commented about how her daughter's imaginary friend is a reality check: "There were times when I would ask Quinn [her daughter] what she was thinking about, and she would say 'Oh, I was just thinking about how Elfie-Welfie [Quinn's imaginary friend] smiles all the time' And, sure enough, I'd been having a rough day and grumbling around"
I've grown up believing that adults can't have imagination be part of their life. Authors of fiction still use their imaginations this way. Is an imaginary world an unhealthy escape, or a healthy way learning about the world, a place to practice social skills?

Hmm...
Thoughts as I go off to bed