Do your characters refuse to cooperate? Are you typing along when, wham!, someone reveals depths you didn't know they had? Something that has the potential to change everything? I love that and I hate it. Love it because it's cool. Hate it because it usually means I may have to rewrite a lot of stuff.
Did I mention I'm on the third rewrite of SEDUCING EVANGELINE? The first time, it wasn't going anywhere. The second, it was going, but the wrong direction. And then I realized I'd given the hero the wrong job, the heroine not enough motivation, and the conflict not enough zing. Now I think I have it right and still I get stuck. I have a subplot involving the heroine's relationship with her sister that is giving me fits. I don't know why. I know why they are estranged. I know they have to work on the relationship. But I don't know how much of that is important to the central problem of the book. And I hate the part where I have to write the scenes, knowing I may lose them in the end anyway. I don't have a problem cutting, but I hate to do the work in the first place if I'm going to cut it. Catch-22, dammit.
(I'm reading Wuthering Heights for the first time ever. OMG. I don't want to put it down. How did this sheltered woman write this story? It's brutal and ugly and amazing and beautiful all at once. What talent.)