I just hope I don't get so involved with outlining that I never get around to writing the actual story.
In the past I have never outlined. In the past, outlining = death for the story, because I get bored. But in the past, I've written fanfic, and my attention span with fanfic is pretty short to begin with. Even my long stories (Andromeda, et al) were written as WIPs where I just wrote and wrote like a crazy person with only half an idea of where I was going and hoped that people would be happy at the end, but if they weren't, well, it was just fanfic. But my original fic story idea has been building for so long, and going through so many versions and iterations - it was going to be a story about... oh, Lord, I don't even remember the character's original name -- ooh wait, it was Lorelei! - and how she pulled a Mulan and wound up in the middle of a war against impossibly advanced invaders. Now it's a story about Gil - originally just another character's bodyguard who wound up being Lorelei's love interest - and how he goes from being a country bumpkin (bitterly clinging to his guns and religion and family, bwahaha) to someone prepared to lead a resistance against unknown but impossibly advanced invaders.
Anyway, after all this work - even if most of the work has been in my brain - I want to do it right, not just fly by the seat of my pants and then have to go back and rewrite hundreds and thousands of words of crap. Rewriting annoys me even more than outlining.
So I'm outlining. Gil and Miri (formerly Lorelei) and Nathan and the Governor and Ivah and all the other characters who haven't been born yet.
Wish me luck.