I liked reading fanfic but thought I would NEVER write it, until one day I had a compelling visual image and needed to tell the story, which became Enough. I like to think about the missing parts of the story, the things that we don't know that could explain why the band are the way they are or do what they do. For instance- when Larry turns on the charm with that poor woman from Graceland in Rattle and Hum- when and where did he learn to do that?! That's a story worth telling. Others like to explore ideas like, if a band member loved someone other than the one they do, or happened to be single at a particular time, what would happen then? I suggest that you just keep mulling it over until you have an idea you can't resist.