I've had this short story idea for over a month and have been gathering good lines, ideas and character moments. Today I finally had the strength to begin writing it. Five scenes in I realized two thirds of my existing material won't make it into the story. It wasn't a waste - it was a cocoon from which the fiction is emerging.
In related news: I'm writing again. I've written more in the last two weeks than in the previous two months. God willing, this short will be out to a market by the end of the month, and by then we'll be off to the races.