One of the things I find amazing with roleplaying is the ability to draw quiet or anxious people into a more engaged role. This article covers many points but the core of it is covered in this quote:
author Sherman Alexie, who was born with hydrocephalus on the Spokane Indian Reservation, shares how the game influenced him in his formative years:
I was a little boy growing up in a dangerous world where nobody gave me a chance to make a saving roll. And yet, while playing Dungeons and Dragons, I pretended so often to have courage and strength that I learned how to display courage and strength in my real life. (Wizards of the Coast, 2004, as quoted in Harrison & Van Haneghan)