I've always been a storyteller. My dad and I still occasionally talk about, when I was little, how I used to insist on hearing stories all the way home from school (it was about an hour long drive). Roleplaying, in my mind, combines the best elements of novels, video games, and movies / tv shows. It is a collaborative effort, and the story is never set. It can switch up in a moment, because of a single sentence my partner threw in, that sparks a whole new idea in my head.
I've never been good at writing by myself. I'm very, very good at coming up with ideas, but until I have a partner to help me flesh it out, it can never get beyond the stages of an idea. Only when I put my idea before someone else can I understand how good, or absolutely terrible and incomprehensible, it is.
Roleplaying also allows me to write without having to worry about getting sued! :D I tend to take my ideas from somewhere else, and then tweak them until they perfectly fit me and my partner. As long as it isn't an obvious copy (in which case it has to go into the fandom section) I don't have to worry about someone being pissed because my idea was too close to their idea!