Writer's Fallout Shelter

I've always been facinated by people who can just launch into a story with no idea of an ending. I have to have everything laid out in point form before I start. I can do it no other way.
I understand about the spelling, grammer and, in my case, chapter numbers. I just get everything down as fast as possible and be damn the rules. Then I work through it to make everything line up, make sense and look pretty. Sometimes my ending changes, sometimes my characters change, but what ever I do - the real rules of writing don't start hitting hard until the second draft.