If you are me, you figure the opening can be used again, and do two treatments of it. Then realize you can skip most of that and start it at a different point. Only your brain decides to inform you that on day two of feeling utterly sick and crappy.
And won't shut up.
On the plus side, I did figure out a little more plot stuff and added a new character into the story. On the other side, I've deleted 3 times the amount I've written on this draft so far.