Writer's blech

I believe I've mentioned once or twice how much I detest revisions. Well, that goes for writing the first draft, too. Usually I write pretty cleanly, able to get what I want down in a minimum of passes. Most of the time.
Not this time. I read a chapter tonight that I absolutely knew was not right, but couldn't put my finger on it. It wasn't until we talked at length about what went on in that chapter and (more importantly what did NOT go on) that I finally figured it out. Unfortunately, this new elucidation means that I get to cut 25 pages from the ms and start in the middle again.
Well, crap.
But at least I am still moving in the story and that's a darn good thing.